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Nanomaterials
Volume 14
Issue 13
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Nanomaterials, Volume 14, Issue 13 (July-1 2024) – 104 articles

Cover Story (view full-size image): This study introduces a novel nanofibrous conductive sensor for detecting limonene, a key plant health biomarker. Using a one-step synthesis via electrospinning and molecular imprinting, polyvinylpyrrolidone (PVP) and polyacrylic acid (PAA) form nanofibers with multiwalled carbon nanotubes (MWCNTs) enhancing conductivity. Functional cavities for limonene recognition are created through UV curing and washing. The sensor, optimized for 50% relative humidity, shows rapid response within 200 seconds and a high selectivity index of 72% for limonene over other VOCs. This innovation holds promise for applications in precision agriculture and environmental monitoring. View this paper
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20 pages, 8631 KiB  
Review
Accelerated Discovery of Halide Perovskite Materials via Computational Methods: A Review
by Ming Sheng, Hui Zhu, Suqin Wang, Zhuang Liu and Guangtao Zhou
Nanomaterials 2024, 14(13), 1167; https://doi.org/10.3390/nano14131167 - 8 Jul 2024
Viewed by 619
Abstract
Halide perovskites have gained considerable attention in materials science due to their exceptional optoelectronic properties, including high absorption coefficients, excellent charge-carrier mobilities, and tunable band gaps, which make them highly promising for applications in photovoltaics, light-emitting diodes, synapses, and other optoelectronic devices. However, [...] Read more.
Halide perovskites have gained considerable attention in materials science due to their exceptional optoelectronic properties, including high absorption coefficients, excellent charge-carrier mobilities, and tunable band gaps, which make them highly promising for applications in photovoltaics, light-emitting diodes, synapses, and other optoelectronic devices. However, challenges such as long-term stability and lead toxicity hinder large-scale commercialization. Computational methods have become essential in this field, providing insights into material properties, enabling the efficient screening of large chemical spaces, and accelerating discovery processes through high-throughput screening and machine learning techniques. This review further discusses the role of computational tools in the accelerated discovery of high-performance halide perovskite materials, like the double perovskites A2BX6 and A2BB′X6, zero-dimensional perovskite A3B2X9, and novel halide perovskite ABX6. This review provides significant insights into how computational methods have accelerated the discovery of high-performance halide perovskite. Challenges and future perspectives are also presented to stimulate further research progress. Full article
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13 pages, 3029 KiB  
Article
Synthesis, Structural Analysis, and Peroxidase-Mimicking Activity of AuPt Branched Nanoparticles
by Silvia Nuti, Javier Fernández-Lodeiro, Jose M. Palomo, José-Luis Capelo-Martinez, Carlos Lodeiro and Adrián Fernández-Lodeiro
Nanomaterials 2024, 14(13), 1166; https://doi.org/10.3390/nano14131166 - 8 Jul 2024
Viewed by 594
Abstract
Bimetallic nanomaterials have generated significant interest across diverse scientific disciplines, due to their unique and tunable properties arising from the synergistic combination of two distinct metallic elements. This study presents a novel approach for synthesizing branched gold–platinum nanoparticles by utilizing poly(allylamine hydrochloride) (PAH)-stabilized [...] Read more.
Bimetallic nanomaterials have generated significant interest across diverse scientific disciplines, due to their unique and tunable properties arising from the synergistic combination of two distinct metallic elements. This study presents a novel approach for synthesizing branched gold–platinum nanoparticles by utilizing poly(allylamine hydrochloride) (PAH)-stabilized branched gold nanoparticles, with a localized surface plasmon resonance (LSPR) response of around 1000 nm, as a template for platinum deposition. This approach allows precise control over nanoparticle size, the LSPR band, and the branching degree at an ambient temperature, without the need for high temperatures or organic solvents. The resulting AuPt branched nanoparticles not only demonstrate optical activity but also enhanced catalytic properties. To evaluate their catalytic potential, we compared the enzymatic capabilities of gold and gold–platinum nanoparticles by examining their peroxidase-like activity in the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB). Our findings revealed that the incorporation of platinum onto the gold surface substantially enhanced the catalytic efficiency, highlighting the potential of these bimetallic nanoparticles in catalytic applications. Full article
(This article belongs to the Special Issue Noble Metal-Based Nanostructures: Optical Properties and Applications)
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10 pages, 3172 KiB  
Article
High-Performance Ultraviolet Photodetectors Based on Nanoporous GaN with a Ga2O3 Single-Crystal Layer
by Junjie Wen, Yuankang Wang, Biao Zhang, Rongrong Chen, Hongyan Zhu, Xinyu Han and Hongdi Xiao
Nanomaterials 2024, 14(13), 1165; https://doi.org/10.3390/nano14131165 - 8 Jul 2024
Viewed by 596
Abstract
The utilization of a nanoporous (NP) GaN fabricated by electrochemical etching has been demonstrated to be effective in the fabrication of a high-performance ultraviolet (UV) photodetector (PD). However, the NP-GaN PD typically exhibits a low light-dark current ratio and slow light response speed. [...] Read more.
The utilization of a nanoporous (NP) GaN fabricated by electrochemical etching has been demonstrated to be effective in the fabrication of a high-performance ultraviolet (UV) photodetector (PD). However, the NP-GaN PD typically exhibits a low light-dark current ratio and slow light response speed. In this study, we present three types of UV PDs based on an unetched GaN, NP-GaN distributed Bragg reflector (DBR), and NP-GaN-DBR with a Ga2O3 single-crystal film (Ga2O3/NP-GaN-DBR). The unetched GaN PD does not exhibit a significant photoresponse. Compared to the NP-GaN-DBR PD device, the Ga2O3/NP-GaN-DBR PD demonstrates a larger light-dark current ratio (6.14 × 103) and higher specific detectivity (8.9 × 1010 Jones) under 365 nm at 5 V bias due to its lower dark current (3.0 × 10−10 A). This reduction in the dark current can be attributed to the insertion of the insulating Ga2O3 between the metal and the NP-GaN-DBR, which provides a thicker barrier thickness and higher barrier height. Additionally, the Ga2O3/NP-GaN-DBR PD device exhibits shorter rise/decay times (0.33/0.23 s) than the NP-GaN-DBR PD, indicating that the growth of a Ga2O3 layer on the DBR effectively reduces the trap density within the NP-GaN DBR structure. Although the device with a Ga2O3 layer presents low photoresponsivity (0.1 A/W), it should be feasible to use Ga2O3 as a dielectric layer based on the above-mentioned reasons. Full article
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16 pages, 7427 KiB  
Article
Nano-Bioremediation of Arsenic and Its Effect on the Biological Activity and Growth of Maize Plants Grown in Highly Arsenic-Contaminated Soil
by Mahmoud El Sharkawy, Arwa A. AL-Huqail, Alya M. Aljuaid, Nourhan Kamal, Esawy Mahmoud, Alaa El-Dein Omara, Nasser Abd El-Kader, Jian Li, Nashaat N. Mahmoud, Ahmed A. El Baroudy, Adel M. Ghoneim and Sahar Mohamed Ismail
Nanomaterials 2024, 14(13), 1164; https://doi.org/10.3390/nano14131164 - 8 Jul 2024
Viewed by 622
Abstract
Arsenic (As)-contaminated soil reduces soil quality and leads to soil degradation, and traditional remediation strategies are expensive or typically produce hazardous by-products that have negative impacts on ecosystems. Therefore, this investigation attempts to assess the impact of As-tolerant bacterial isolates via a bacterial [...] Read more.
Arsenic (As)-contaminated soil reduces soil quality and leads to soil degradation, and traditional remediation strategies are expensive or typically produce hazardous by-products that have negative impacts on ecosystems. Therefore, this investigation attempts to assess the impact of As-tolerant bacterial isolates via a bacterial Rhizobim nepotum strain (B1), a bacterial Glutamicibacter halophytocola strain (B2), and MgO-NPs (N) and their combinations on the arsenic content, biological activity, and growth characteristics of maize plants cultivated in highly As-contaminated soil (300 mg As Kg−1). The results indicated that the spectroscopic characterization of MgO-NPs contained functional groups (e.g., Mg-O, OH, and Si-O-Si) and possessed a large surface area. Under As stress, its addition boosted the growth of plants, biomass, and chlorophyll levels while decreasing As uptake. Co-inoculation of R. nepotum and G. halophytocola had the highest significant values for chlorophyll content, soil organic matter (SOM), microbial biomass (MBC), dehydrogenase activity (DHA), and total number of bacteria compared to other treatments, which played an essential role in increasing maize growth. The addition of R. nepotum and G. halophytocola alone or in combination with MgO-NPs significantly decreased As uptake and increased the biological activity and growth characteristics of maize plants cultivated in highly arsenic-contaminated soil. Considering the results of this investigation, the combination of G. halophytocola with MgO-NPs can be used as a nanobioremediation strategy for remediating severely arsenic-contaminated soil and also improving the biological activity and growth parameters of maize plants. Full article
(This article belongs to the Special Issue Applications of Nanomaterials in Environmental Remediation and Pollution Control)
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24 pages, 7321 KiB  
Article
Catalytic Ozonation of Pharmaceuticals Using CeO2-CeTiOx-Doped Crossflow Ultrafiltration Ceramic Membranes
by Nikoletta Tsiarta, Silvia Morović, Vilko Mandić, Ivana Panžić, Roko Blažic, Lidija Ćurković and Wolfgang Gernjak
Nanomaterials 2024, 14(13), 1163; https://doi.org/10.3390/nano14131163 - 7 Jul 2024
Viewed by 649
Abstract
The removal of persistent organic micropollutants (OMPs) from secondary effluent in wastewater treatment plants is critical for meeting water reuse standards. Traditional treatment methods often fail to adequately degrade these contaminants. This study explored the efficacy of a hybrid ozonation membrane filtration (HOMF) [...] Read more.
The removal of persistent organic micropollutants (OMPs) from secondary effluent in wastewater treatment plants is critical for meeting water reuse standards. Traditional treatment methods often fail to adequately degrade these contaminants. This study explored the efficacy of a hybrid ozonation membrane filtration (HOMF) process using CeO2 and CeTiOx-doped ceramic crossflow ultrafiltration ceramic membranes for the degradation of OMPs. Hollow ceramic membranes (CM) with a 300 kDa molecular weight cut-off (MWCO) were modified to serve as substrates for catalytic nanosized metal oxides in a crossflow and inside-out operational configuration. Three types of depositions were tested: a single layer of CeO2, a single layer of CeTiOx, and a combined layer of CeO2 + CeTiOx. These catalytic nanoparticles were distributed uniformly using a solution-based method supported by vacuum infiltration to ensure high-throughput deposition. The results demonstrated successful infiltration of the metal oxides, although the yield permeability and transmembrane flow varied, following this order: pristine > CeTiOx > CeO2 > CeO2 + CeTiOx. Four OMPs were examined: two easily degraded by ozone (carbamazepine and diclofenac) and two recalcitrant (ibuprofen and pCBA). The highest OMP degradation was observed in demineralized water, particularly with the CeO2 + CeTiOx modification, suggesting O3 decomposition to hydroxyl radicals. The increased resistance in the modified membranes contributed to the adsorption phenomena. The degradation efficiency decreased in secondary effluent due to competition with the organic and inorganic load, highlighting the challenges in complex water matrices. Full article
(This article belongs to the Special Issue Advances and Recent Trends in Functional Membranes and Nanostructured Materials for Environmental Applications)
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25 pages, 8428 KiB  
Article
Anisotropy of Electrical and Thermal Conductivity in High-Density Graphite Foils
by Vladimir A. Shulyak, Nikolai S. Morozov, Alexandra V. Gracheva, Maria D. Gritskevich, Sergei N. Chebotarev and Viktor V. Avdeev
Nanomaterials 2024, 14(13), 1162; https://doi.org/10.3390/nano14131162 - 7 Jul 2024
Viewed by 529
Abstract
Flexible graphite foils with varying thicknesses (S = 282 ± 5 μm, M = 494 ± 7 μm, L = 746 ± 8 μm) and an initial density of 0.70 g/cm3 were obtained using the nitrate method. The specific electrical and thermal [...] Read more.
Flexible graphite foils with varying thicknesses (S = 282 ± 5 μm, M = 494 ± 7 μm, L = 746 ± 8 μm) and an initial density of 0.70 g/cm3 were obtained using the nitrate method. The specific electrical and thermal conductivity of these foils were investigated. As the density increased from 0.70 g/cm3 to 1.75 g/cm3, the specific electrical conductivity increased from 69 to 192 kS/m and the thermal conductivity increased from 109 to 326 W/(m·K) due to the rolling of graphite foils. The study showed that conductivity and anisotropy depend on the shape, orientation, and contact area of thermally expanded graphite (TEG) mesoparticles (mesostructural factor), and the crystal structure of nanocrystallites (nanostructural factor). A proposed mesostructural model explained these increases, with denser foils showing elongated, narrowed TEG particles and larger contact areas, confirmed by electron microscopy results. For graphite foils 200 and 750 μm thick, increased density led to a larger coherent scattering region, likely due to the rotation of graphite mesoparticles under mechanical action, while thinner foils (<200 μm) with densities > 1.7 g/cm3 showed increased plastic deformation, indicated by a sharp reduction in the coherent scattering region size. This was also evident from the decrease in misorientation angles with increasing density. Rolling reduced nanocrystallite misorientation angles along the rolling direction compared to the transverse direction (TD) (for 1.75 g/cm3 density ΔMA = 1.2° (S), 2.6° (M), and 2.4° (L)), explaining the observed anisotropy in the electrical and mechanical properties of the rolled graphite foils. X-ray analysis confirmed the preferred nanocrystallite orientation and anisotropy coefficients (A) using Kearns parameters, which aligned well with experimental measurements (for L series foils calculated as: A0.70 = 1.05, A1.30 = 1.10, and A1.75 = 1.16). These calculated values corresponded well with the experimental measurements of specific electrical conductivity, where the anisotropy coefficient changed from 1.00 to 1.16 and mechanical properties varied from 0.98 to 1.13. Full article
(This article belongs to the Section 2D and Carbon Nanomaterials)
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11 pages, 2438 KiB  
Article
Positive Effects of Guanidinium Salt Post-Treatment on Multi-Cation Mixed Halide Perovskite Solar Cells
by Damir Aidarkhanov, Ikenna Henry Idu, Xianfang Zhou, Dawei Duan, Fei Wang, Hanlin Hu and Annie Ng
Nanomaterials 2024, 14(13), 1161; https://doi.org/10.3390/nano14131161 - 7 Jul 2024
Viewed by 652
Abstract
As one of the most promising photovoltaic technologies, perovskite solar cells (PSCs) exhibit high absorption coefficients, tunable bandgaps, large carrier mobilities, and versatile fabrication techniques. Nevertheless, the commercialization of the technology is hindered by poor material stability, short device lifetimes and the scalability [...] Read more.
As one of the most promising photovoltaic technologies, perovskite solar cells (PSCs) exhibit high absorption coefficients, tunable bandgaps, large carrier mobilities, and versatile fabrication techniques. Nevertheless, the commercialization of the technology is hindered by poor material stability, short device lifetimes and the scalability of fabrication techniques. To address these technological drawbacks, various strategies have been explored, with one particularly promising approach involving the formation of a low-dimensional layer on the surface of the three-dimensional perovskite film. In this work, we demonstrate the use of guanidinium tetrafluoroborate, CH6BF4N3, (GATFB) as a post-treatment step to enhance the performance of PSCs. Compared with the control sample, the application of GATFB improves the film surface topology, reduces surface defects, suppresses non-radiative recombination, and optimizes band alignment within the device. These positive effects reduce recombination losses and enhance charge transport in the device, resulting in PSCs with an open-circuit voltage (VOC) of 1.18 V and a power conversion efficiency (PCE) of 19.7%. The results obtained in this work exhibit the potential of integrating low-dimensional structures in PSCs as an effective approach to enhance the overall device performance, providing useful information for further advancement in this rapidly evolving field of photovoltaic technology. Full article
(This article belongs to the Section Solar Energy and Solar Cells)
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14 pages, 4047 KiB  
Article
Bi-Directional Full-Color Generation and Tri-Channel Information Encoding Based on a Plasmonic Metasurface
by Dewang Huo and Guoqiang Li
Nanomaterials 2024, 14(13), 1160; https://doi.org/10.3390/nano14131160 - 7 Jul 2024
Viewed by 504
Abstract
Dynamic optical structural color is always desired in various display applications and usually involves active materials. Full-color generation, especially bi-directional full-color generation in both reflective and transmissive modes, without any active materials included, has rarely been investigated. Herein, we demonstrate a scheme of [...] Read more.
Dynamic optical structural color is always desired in various display applications and usually involves active materials. Full-color generation, especially bi-directional full-color generation in both reflective and transmissive modes, without any active materials included, has rarely been investigated. Herein, we demonstrate a scheme of bi-directional full-color generation based on a plasmonic metasurface modulated by the rotation of the polarization angle of the incident light without varying the geometry and the optical properties of the materials and the environment where the metasurface resides. The metasurface unit cell consists of plasmonic modules aligning in three directions and is patterned in a square array. The metasurface structural color device is numerically confirmed to generate full colors in both reflection and transmission. Based on the proposed polarization-dependent structural color, the information encoding process is demonstrated for three multiplexed animal images and quick-responsive (QR) codes to verify the efficient information encoding and decoding of the proposed scheme. In the simulation, the animals can be seen under different polarization incidences, and the QR codes can be successfully decoded by the polarization rotation in transmission. The proposed bi-directional full-color generation metasurface has great potential in applications such as kaleidoscope generation, anti-counterfeiting, dynamic color display, and optical information encoding. Full article
(This article belongs to the Special Issue Advances in Photonic Metasurfaces and Metastructures)
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14 pages, 3765 KiB  
Article
Optimization of Thermoelectric Nanoantenna for Massive High-Output-Voltage Arrays
by Mohamad Khoirul Anam, Yudhistira Yudhistira and Sangjo Choi
Nanomaterials 2024, 14(13), 1159; https://doi.org/10.3390/nano14131159 - 7 Jul 2024
Viewed by 583
Abstract
Thermoelectric nanoantennas have been extensively investigated due to their ability to directly convert infrared (IR) radiation into direct current without an additional rectification device. In this study, we introduce a thermoelectric nanoantenna geometry for maximum output voltage (Voc) and propose [...] Read more.
Thermoelectric nanoantennas have been extensively investigated due to their ability to directly convert infrared (IR) radiation into direct current without an additional rectification device. In this study, we introduce a thermoelectric nanoantenna geometry for maximum output voltage (Voc) and propose an optimal series array configuration with a finite number of antennas to enhance the Voc. A finite and open-ended SiO2 substrate, with a thickness of a quarter-effective wavelength at a frequency of 28.3 THz, is used to generate standing waves within the substrate. An array of antennas is then positioned optimally on the substrate to maximize the temperature difference (∆T) between hot and cold areas, thereby increasing the average Voc per antenna element. In numerical simulations, a linearly polarized incident wave with a power density of 1.42 W/cm2 is applied to the structure. The results show that a single antenna with the optimum geometry on a substrate measuring 35 µm × 35 µm generates a ∆T of 64.89 mK, corresponding to a Voc of 1.75 µV. Finally, a series array of 5 × 6 thermoelectric nanoantennas on a 150 µm × 75 µm substrate including measurement pads achieves an average ∆T of 49.60 mK with a total Voc of 40.18 µV, resulting in an average Voc of 1.34 µV per antenna element and a voltage responsivity (βv) of 0.77 V/W. This value, achieved solely by optimizing the antenna geometry and open-ended substrate, matches or exceeds the Voc and βv of approximately 1 µV and 0.66 V/W, respectively, from suspended thermoelectric antenna arrays over air cavities. Therefore, the proposed thermoelectric nanoantenna array device, characterized by high stability and ease of fabrication, is suitable for manufacturing massive nanoantenna arrays for high-output IR-DC energy harvesters. Full article
(This article belongs to the Special Issue Harvesting Electromagnetic Fields with Nanomaterials from Microwaves to Ultraviolet)
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13 pages, 2652 KiB  
Article
Three-Dimensional Nickel Foam-Based Lithiophilic LPP-Ni3S2@Ni Current Collector for Dendrite-Free Lithium Anode
by Xin Zhang, Linli Guo, Sheng Huang and Dongmei Han
Nanomaterials 2024, 14(13), 1158; https://doi.org/10.3390/nano14131158 - 7 Jul 2024
Viewed by 537
Abstract
Lithium metal has been treated as one of the most promising anode materials for next-generation rechargeable batteries due to its extremely high theoretical capacity. However, its practical application is hindered by inhomogeneous lithium deposition and uncontrolled dendrite growth. In this work, we prepared [...] Read more.
Lithium metal has been treated as one of the most promising anode materials for next-generation rechargeable batteries due to its extremely high theoretical capacity. However, its practical application is hindered by inhomogeneous lithium deposition and uncontrolled dendrite growth. In this work, we prepared a three-dimensional nickel foam (NF)-based current collector with a lithiophilic interface layer through facile hydrothermal and coating methods. The lithiophilic Ni3S2 array synthesized via a hydrothermal method has been demonstrated to facilitate the nucleation of Li+. Moreover, it has been observed that the outer coating comprising LPP effectively enhances the inward diffusion of Li+. Additionally, this interface layer can serve as an isolating barrier between the electrodes and the electrolyte. The prepared LPP-Ni3S2@Ni shows significant reversibility both in symmetric cells (1200 h, 1 mA cm−2) and half-cells (CE: 99.60%, 500 cycles, 1 mA cm−2) with low interfacial resistance (35 Ω). Full cells with LiFePO4 as a cathode also exhibit promising electrochemical performance with over 76.78% capacity retention over 200 cycles at 1 C. Full article
(This article belongs to the Special Issue Nanoscale Catalytic Synthesis of Biodegradable or Biobased Polymeric Materials from Carbon Dioxide)
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16 pages, 5595 KiB  
Article
Green Synthesis of CuO Nanoparticles from Macroalgae Ulva lactuca and Gracilaria verrucosa
by Marta Marmiroli, Marco Villani, Paolina Scarponi, Silvia Carlo, Luca Pagano, Valentina Sinisi, Laura Lazzarini, Milica Pavlicevic and Nelson Marmiroli
Nanomaterials 2024, 14(13), 1157; https://doi.org/10.3390/nano14131157 - 6 Jul 2024
Viewed by 711
Abstract
Macroalgae seaweeds such as Ulva lactuca and Gracilaria verrucosa cause problems on the northern coast of the Italian Adriatic Sea because their overabundance hinders the growth of cultivated clams, Rudatapes philippinarum. This study focused on the green synthesis of CuO nanoparticles from [...] Read more.
Macroalgae seaweeds such as Ulva lactuca and Gracilaria verrucosa cause problems on the northern coast of the Italian Adriatic Sea because their overabundance hinders the growth of cultivated clams, Rudatapes philippinarum. This study focused on the green synthesis of CuO nanoparticles from U. lactuca and G. verrucosa. The biosynthesized CuO NPs were successfully characterized using FTIR, XRD, HRTEM/EDX, and zeta potential. Nanoparticles from the two different algae species are essentially identical, with the same physical characteristics and almost the same antimicrobial activities. We have not investigated the cause of this identity, but it seems likely to arise from the reaction of Cu with the same algae metabolites in both species. The study demonstrates that it is possible to obtain useful products from these macroalgae through a green synthesis approach and that they should be considered as not just a cause of environmental and economic damage but also as a potential source of income. Full article
(This article belongs to the Special Issue Advanced Studies in Bionanomaterials)
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11 pages, 4100 KiB  
Article
Influence of Long Milling Time on the Electrical Resistivity of Nanocrystalline Ni2MnSn Heusler Alloy Obtained by Mechanosynthesis
by Florin Popa, Traian Florin Marinca, Niculina Argentina Sechel, Dan Ioan Frunzӑ and Ionel Chicinaș
Nanomaterials 2024, 14(13), 1156; https://doi.org/10.3390/nano14131156 - 6 Jul 2024
Viewed by 398
Abstract
A Ni2MnSn Heusler alloy was obtained as a single B2 phase after 12 h of mechanical milling. The influence of prolonged milling on the phase stability was analysed for milling times up to 50 h, related to mean crystallite size, [...] Read more.
A Ni2MnSn Heusler alloy was obtained as a single B2 phase after 12 h of mechanical milling. The influence of prolonged milling on the phase stability was analysed for milling times up to 50 h, related to mean crystallite size, lattice strain, and electrical resistivity. The nature of the powders in the milled range was found to be nanocrystalline, with a mean crystallite size of about 33 ± 2 nm. An evaluation of the internal stresses induced by milling was performed, a linear behaviour was found, and a coefficient of the internal stress increase with milling time was proposed. Particle size distributions of milled samples were analysed, and the morphology of the powders was visualised by scanning electron microscopy. The elemental distribution of milled samples was quantified by energy-dispersive X-ray spectroscopy. Electrical resistivity measurements were performed on compacted samples, and their behaviour with milling time was analysed. Full article
(This article belongs to the Special Issue Nanostructural Processing Effects in Shape Memory Alloys)
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16 pages, 3544 KiB  
Article
Flexible CNT-Interpenetrating Hierarchically Porous Sulfurized Polyacrylonitrile (CIHP-SPAN) Electrodes for High-Rate Lithium-Sulfur (Li-S) Batteries
by Jiashuo Shao, Cheng Huang, Qi Zhu, Nan Sun, Junning Zhang, Rihui Wang, Yunxiang Chen and Zongtao Zhang
Nanomaterials 2024, 14(13), 1155; https://doi.org/10.3390/nano14131155 - 6 Jul 2024
Viewed by 557
Abstract
Sulfurized polyacrylonitrile (SPAN) is a promising cathode material for lithium-sulfur batteries owing to its reversible solid–solid conversion for high-energy-density batteries. However, the sluggish reaction kinetics of SPAN cathodes significantly limit their output capacity, especially at high cycling rates. Herein, a CNT-interpenetrating hierarchically porous [...] Read more.
Sulfurized polyacrylonitrile (SPAN) is a promising cathode material for lithium-sulfur batteries owing to its reversible solid–solid conversion for high-energy-density batteries. However, the sluggish reaction kinetics of SPAN cathodes significantly limit their output capacity, especially at high cycling rates. Herein, a CNT-interpenetrating hierarchically porous SPAN electrode is developed by a simple phase-separation method. Flexible self-supporting SPAN cathodes with fast electron/ion pathways are synthesized without additional binders, and exceptional high-rate cycling performances are obtained even with substantial sulfur loading. For batteries assembled with this special cathode, an impressive initial discharge capacity of 1090 mAh g−1 and a retained capacity of 800 mAh g−1 are obtained after 1000 cycles at 1 C with a sulfur loading of 1.5 mg cm−2. Furthermore, by incorporating V2O5 anchored carbon fiber as an interlayer with adsorption and catalysis function, a high initial capacity of 614.8 mAh g−1 and a notable sustained capacity of 500 mAh g−1 after 500 cycles at 5 C are achieved, with an ultralow decay rate of 0.037% per cycle with a sulfur loading of 1.5 mg cm−2. The feasible construction of flexible SPAN electrodes with enhanced cycling performance enlists the current processing as a promising strategy for novel high-rate lithium-sulfur batteries and other emerging battery electrodes. Full article
(This article belongs to the Special Issue Application of Nanomaterials in Solid-State Energy Storage Materials and Batteries (Second Edition))
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11 pages, 2220 KiB  
Article
Plasma-Etched Black GaAs Nanoarrays with Gradient Refractive Index Profile for Broadband, Omnidirectional, and Polarization-Independent Antireflection
by Yi-Fan Huang, Yi-Jun Jen, Varad A. Modak, Li-Chyong Chen and Kuei-Hsien Chen
Nanomaterials 2024, 14(13), 1154; https://doi.org/10.3390/nano14131154 - 6 Jul 2024
Viewed by 742
Abstract
Black GaAs nanotip arrays (NTs) with 3300 nm lengths were fabricated via self-masked plasma etching. We show, both experimentally and numerically, that these NTs, with three gradient refractive index layers, effectively suppress Fresnel reflections at the air–GaAs interface over a broad range of [...] Read more.
Black GaAs nanotip arrays (NTs) with 3300 nm lengths were fabricated via self-masked plasma etching. We show, both experimentally and numerically, that these NTs, with three gradient refractive index layers, effectively suppress Fresnel reflections at the air–GaAs interface over a broad range of wavelengths. These NTs exhibit exceptional UV-Vis light absorption (up to 99%) and maintain high NIR absorption (33–60%) compared to bare GaAs. Moreover, possessing a graded layer with a low refractive index (n = 1.01 to 1.12), they achieve angular and polarization-independent antireflection properties exceeding 80° at 632.8 nm, aligning with perfect antireflective coating theory predictions. This approach is anticipated to enhance the performance of optoelectronic devices across a wide range of applications. Full article
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11 pages, 2673 KiB  
Article
Preparation of Thermochromic Vanadium Dioxide Films Assisted by Machine Learning
by Gaoyang Xiong, Haining Ji, Yongxing Chen, Bin Liu, Yi Wang, Peng Long, Jinfang Zeng, Jundong Tao and Cong Deng
Nanomaterials 2024, 14(13), 1153; https://doi.org/10.3390/nano14131153 - 6 Jul 2024
Viewed by 625
Abstract
In recent years, smart windows have attracted widespread attention due to their ability to respond to external stimuli such as light, heat, and electricity, thereby intelligently adjusting the ultraviolet, visible, and near-infrared light in solar radiation. VO2(M) undergoes a reversible phase [...] Read more.
In recent years, smart windows have attracted widespread attention due to their ability to respond to external stimuli such as light, heat, and electricity, thereby intelligently adjusting the ultraviolet, visible, and near-infrared light in solar radiation. VO2(M) undergoes a reversible phase transition from an insulating phase (monoclinic, M) to a metallic phase (rutile, R) at a critical temperature of 68 °C, resulting in a significant difference in near-infrared transmittance, which is particularly suitable for use in energy-saving smart windows. However, due to the multiple valence states of vanadium ions and the multiphase characteristics of VO2, there are still challenges in preparing pure-phase VO2(M). Machine learning (ML) can learn and generate models capable of predicting unknown data from vast datasets, thereby avoiding the wastage of experimental resources and reducing time costs associated with material preparation optimization. Hence, in this paper, four ML algorithms, namely multi-layer perceptron (MLP), random forest (RF), support vector machine (SVM), and extreme gradient boosting (XGB), were employed to explore the parameters for the successful preparation of VO2(M) films via magnetron sputtering. A comprehensive performance evaluation was conducted on these four models. The results indicated that XGB was the top-performing model, achieving a prediction accuracy of up to 88.52%. A feature importance analysis using the SHAP method revealed that substrate temperature had an essential impact on the preparation of VO2(M). Furthermore, characteristic parameters such as sputtering power, substrate temperature, and substrate type were optimized to obtain pure-phase VO2(M) films. Finally, it was experimentally verified that VO2(M) films can be successfully prepared using optimized parameters. These findings suggest that ML-assisted material preparation is highly feasible, substantially reducing resource wastage resulting from experimental trial and error, thereby promoting research on material preparation optimization. Full article
(This article belongs to the Special Issue Nanomaterials for Chemical Engineering (Volume III))
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11 pages, 5225 KiB  
Article
Electrospinning and Partial Etching Behaviors of Core–Shell Nanofibers Directly Electrospun on Mesh Substrates for Application in a Cover-Free Compact Air Filter
by Yujung Lee, Seungwoo Jung and Ji Sun Yun
Nanomaterials 2024, 14(13), 1152; https://doi.org/10.3390/nano14131152 - 5 Jul 2024
Viewed by 507
Abstract
The exposure of workers to propylene glycol monomethyl ether acetate (PGMEA) in manufacturing environments can result in potential health risks. Therefore, systems for PGMEA removal are required for indoor air quality control. In this study, core–shell zeolite socony mobil-5 (ZSM-5)/polyvinylpyrrolidone–polyvinylidene fluoride nanofibers were [...] Read more.
The exposure of workers to propylene glycol monomethyl ether acetate (PGMEA) in manufacturing environments can result in potential health risks. Therefore, systems for PGMEA removal are required for indoor air quality control. In this study, core–shell zeolite socony mobil-5 (ZSM-5)/polyvinylpyrrolidone–polyvinylidene fluoride nanofibers were directly electrospun and partially wet-etched on a mesh substrate to develop a cover-free compact PGMEA air filter. The electrospinning behaviors of the core–shell nanofibers were investigated to optimize the electrospinning time and humidity and to enable the manufacture of thin and light air-filter layers. The partial wet etching of the nanofibers was undertaken using different etching solvents and times to ensure the exposure of the active sites of ZSM-5. The performances of the ZSM-5/PVDF nanofiber air filters were assessed by measuring five consecutive PGMEA adsorption–desorption cycles at different desorption temperatures. The synthesized material remained stable upon repeated adsorption–desorption cycles and could be regenerated at a low desorption temperature (80 °C), demonstrating a consistent adsorption performance upon prolonged adsorption–desorption cycling and low energy consumption during regeneration. The results of this study provide new insights into the design of industrial air filters using functional ceramic/polymer nanofibers and the application of these filters. Full article
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17 pages, 6042 KiB  
Article
Synthesis and Superficial Modification “In Situ” of Copper Selenide (Cu2-x Se) Nanoparticles and Their Antibacterial Activity
by José Manuel Mata-Padilla, José Ángel Ledón-Smith, Marissa Pérez-Alvarez, Gregorio Cadenas-Pliego, Enrique Díaz Barriga-Castro, Odilia Pérez-Camacho, Christian Javier Cabello-Alvarado and Rodolfo Silva
Nanomaterials 2024, 14(13), 1151; https://doi.org/10.3390/nano14131151 - 4 Jul 2024
Viewed by 906
Abstract
Copper selenide nanoparticles (Cu2-x Se NPs) have received a lot of attention in recent decades due to their interesting properties and potential applications in various areas such as electronics, health, solar cells, etc. In this study, details of the synthesis and characterization [...] Read more.
Copper selenide nanoparticles (Cu2-x Se NPs) have received a lot of attention in recent decades due to their interesting properties and potential applications in various areas such as electronics, health, solar cells, etc. In this study, details of the synthesis and characterization of copper selenide nanoparticles modified with gum arabic (GA) are reported. Also, through transmission electronic microscopy (TEM) analysis, the transformation of the morphology and particle size of copper selenide nanoparticles in aqueous solution was studied. In addition, we present an antimicrobial study with different microorganisms such as Staphylococcus aureus (S. aureus), Escherichia coli (E. coli) and Candida albiacans (C. albicans). Copper selenide nanoparticles were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry analysis (DSC) and TEM. XRD confirmed the crystal-line structure of the nanoparticles such as cubic berzelanite with a particle size of 6 nm ± 0.5. FTIR and TGA corroborated the surface modification of copper selenide nanoparticles with gum arabic, and DSC suggested a change in the structural phase from cubic to hexagonal. TEM analysis demonstrated that the surface modification of the Cu2-x Se NPs stabilized the nanostructure of the particles, preventing changes in the morphology and particle size. The antimicrobial susceptibility analysis of copper selenide nanoparticles indicated that they have the ability to inhibit the microbial growth of Staphylococcus aureus, Escherichia coli and Candida albicans. Full article
(This article belongs to the Special Issue Biosynthesis and Green Synthesis of Nanomaterials: New Methodologies and Results, 2nd Edition)
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14 pages, 6723 KiB  
Article
A Novel Terahertz Metamaterial Microfluidic Sensing Chip for Ultra-Sensitive Detection
by Yuan Zhang, Keke Jia, Hongyi Ge, Xiaodi Ji, Yuying Jiang, Yuwei Bu, Yujie Zhang and Qingcheng Sun
Nanomaterials 2024, 14(13), 1150; https://doi.org/10.3390/nano14131150 - 4 Jul 2024
Viewed by 756
Abstract
A terahertz metamaterial microfluidic sensing chip for ultrasensitive detection is proposed to investigate the response of substances to terahertz radiation in liquid environments and enhance the molecular fingerprinting of trace substances. The structure consists of a cover layer, a metal microstructure, a microfluidic [...] Read more.
A terahertz metamaterial microfluidic sensing chip for ultrasensitive detection is proposed to investigate the response of substances to terahertz radiation in liquid environments and enhance the molecular fingerprinting of trace substances. The structure consists of a cover layer, a metal microstructure, a microfluidic channel, a metal reflective layer, and a buffer layer from top to bottom, respectively. The simulation results show that there are three obvious resonance absorption peaks in the range of 1.5–3.0 THz and the absorption intensities are all above 90%. Among them, the absorption intensity at M1 = 1.971 THz is 99.99%, which is close to the perfect absorption, and its refractive index sensitivity and Q-factor are 859 GHz/RIU and 23, respectively, showing excellent sensing characteristics. In addition, impedance matching and equivalent circuit theory are introduced in this paper to further analyze the physical mechanism of the sensor. Finally, we perform numerical simulations using refractive index data of normal and cancer cells, and the results show that the sensor can distinguish different types of cells well. The chip can reduce the sample pretreatment time as well as enhance the interaction between terahertz waves and matter, which can be used for early disease screening and food quality and safety detection in the future. Full article
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16 pages, 9245 KiB  
Article
Melanin-Based Nanoparticles for Lymph Node Tattooing: Experimental, Histopathological and Ultrastructural Study
by Marta Baselga, Antonio Güemes, Cristina Yus, Teresa Alejo, Víctor Sebastián, Dolores Arribas, Gracia Mendoza, Eva Monleón and Manuel Arruebo
Nanomaterials 2024, 14(13), 1149; https://doi.org/10.3390/nano14131149 - 4 Jul 2024
Viewed by 605
Abstract
In breast cancer, Targeted Axillary Dissection (TAD) allows for the selective excision of the sentinel lymph node (SLN) during primary tumor surgery. TAD consists of the resection of labelled SLNs prior to neoadjuvant chemotherapy (NACT). Numerous clinical and preclinical studies have explored the [...] Read more.
In breast cancer, Targeted Axillary Dissection (TAD) allows for the selective excision of the sentinel lymph node (SLN) during primary tumor surgery. TAD consists of the resection of labelled SLNs prior to neoadjuvant chemotherapy (NACT). Numerous clinical and preclinical studies have explored the use of carbon-based colloids for SLN tattooing prior to NACT. However, carbon vectors show varying degrees of inflammatory reactions and, in about one fifth of cases, carbon particles migrate via the lymphatic pathway to other nodes, causing the SLN to mismatch the tattooed node. To overcome these limitations, in this study, we explored the use of melanin as a staining endogenous pigment. We synthesized and characterized melanin-loaded polymeric nanoparticles (Mel-NPs) and used them to tattoo lymph nodes in pig animal models given the similarity in the size of the human and pig nodes. Mel-NPs tattooed lymph nodes showed high identification rates, reaching 83.3% positive identification 16 weeks after tattooing. We did not observe any reduction in the identification as time increased, implying that the colloid is stable in the lymph node tissue. In addition, we performed histological and ultrastructural studies to characterize the biological behavior of the tag. We observed foreign-body-like granulomatous inflammatory responses associated with Mel-NPs, characterized by the formation of multinucleated giant cells. In addition, electron microscopy studies showed that uptake is mainly performed by macrophages, and that macrophages undergo cellular damage associated with particle uptake. Full article
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25 pages, 14032 KiB  
Article
Effect of Co-Sputtered Copper and Titanium Oxide Coatings on Bacterial Resistance and Cytocompatibility of Osteoblast Cells
by Maria P. Nikolova, Iliyan Tzvetkov, Tanya V. Dimitrova, Veronika L. Ivanova, Yordan Handzhiyski, Andreana Andreeva, Stefan Valkov, Maria Ormanova and Margarita D. Apostolova
Nanomaterials 2024, 14(13), 1148; https://doi.org/10.3390/nano14131148 - 4 Jul 2024
Viewed by 638
Abstract
One of the primary risk factors for implant failure is thought to be implant-related infections during the early healing phase. Developing coatings with cell stimulatory behaviour and bacterial adhesion control is still difficult for bone implants. This study proposes an approach for one-step [...] Read more.
One of the primary risk factors for implant failure is thought to be implant-related infections during the early healing phase. Developing coatings with cell stimulatory behaviour and bacterial adhesion control is still difficult for bone implants. This study proposes an approach for one-step deposition of biocompatible and antimicrobial Cu-doped TiO2 coatings via glow-discharge sputtering of a mosaic target. During the deposition, the bias of the Ti6Al4V substrates was changed. Structure examination, phase analysis, and surface morphology were carried out using X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The hardness values and hydrophilic and corrosion performance were also evaluated together with cytocompatible and antibacterial examinations against E. coli and S. aureus. The results show great chemical and phase control of the bias identifying rutile, anatase, CuO, or ternary oxide phases. It was found that by increasing the substrate bias from 0 to −50 V the Cu content increased from 15.3 up to 20.7 at% while at a high bias of −100 V, the copper content reduced to 3 at%. Simultaneously, apart from the Cu2+ state, Cu1+ is also found in the biased samples. Compared with the bare alloy, the hardness, the water contact angle and corrosion resistance of the biased coatings increased. According to an assessment of in vitro cytocompatibility, all coatings were found to be nontoxic to MG-63 osteoblast cells over the time studied. Copper release and cell-surface interactions generated an antibacterial effect against E. coli and S. aureus strains. The −50 V biased coating combined the most successful results in inhibiting bacterial growth and eliciting the proper responses from osteoblastic cells because of its phase composition, electrochemical stability, hydrophilicity, improved substrate adhesion, and surface roughness. Using this novel surface modification approach, we achieved multifunctionality through controlled copper content and oxide phase composition in the sputtered films. Full article
(This article belongs to the Special Issue 2D Nanomaterials for Medical Applications)
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12 pages, 4425 KiB  
Article
Green Synthesis of Silver Nanoparticles from Anthocyanin Extracts of Peruvian Purple Potato INIA 328—Kulli papa
by Antony Alexander Neciosup-Puican, Luz Pérez-Tulich, Wiliam Trujillo and Carolina Parada-Quinayá
Nanomaterials 2024, 14(13), 1147; https://doi.org/10.3390/nano14131147 - 4 Jul 2024
Viewed by 710
Abstract
In this work, AgNPs were synthesized using an anthocyanin extract from Peruvian purple potato INIA 328—Kulli papa. The anthocyanin extract was obtained through a conventional extraction with acidified ethanolic aqueous solvent. This extract acted as both a reducing and stabilizing agent [...] Read more.
In this work, AgNPs were synthesized using an anthocyanin extract from Peruvian purple potato INIA 328—Kulli papa. The anthocyanin extract was obtained through a conventional extraction with acidified ethanolic aqueous solvent. This extract acted as both a reducing and stabilizing agent for the reduction of silver ions. Optimization of synthesis parameters, including pH, reaction time, and silver nitrate (AgNO3) concentration, led to the optimal formation of AgNPs at pH 10, with a reaction time of 30 min and an AgNO3 concentration of 5 mM. Characterization techniques such as X-ray diffraction (XRD) and dynamic light scattering (DLS) revealed that the AgNPs had a crystallite size of 9.42 nm and a hydrodynamic diameter of 21.6 nm, with a zeta potential of −42.03 mV, indicating favorable colloidal stability. Fourier Transform Infrared (FTIR) analysis confirmed the presence of anthocyanin functional groups on the surface of the AgNPs, contributing to their stability. Furthermore, the bacterial activity of the AgNPs was evaluated by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). For E. coli, the MIC was 0.5 mM (0.05 mg/mL) and the MBC was 4.5 mM (0.49 mg/mL). Similarly, for S. aureus, the MIC was 0.5 mM (0.05 mg/mL) and the MBC was 4.0 mM (0.43 mg/mL). These results highlight the potential benefits of AgNPs synthesized from Peruvian purple potato anthocyanin extract, both in biomedical and environmental contexts. Full article
(This article belongs to the Section Environmental Nanoscience and Nanotechnology)
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13 pages, 2517 KiB  
Article
Optimizing P3HT/PCBM-Based Organic Photodetector Performance: Insights from SCAPS 1D Simulation Studies
by Ahmet Sait Alali, Murat Oduncuoglu and Farid Touati
Nanomaterials 2024, 14(13), 1146; https://doi.org/10.3390/nano14131146 - 4 Jul 2024
Viewed by 960
Abstract
Organic electronics have great potential due to their flexible structure, high performance, and their ability to build effective and low-cost photodetectors. We investigated the parameters of the P3HT and PCBM layers for device performance and optimization. SCAPS-1D simulations were employed to optimize the [...] Read more.
Organic electronics have great potential due to their flexible structure, high performance, and their ability to build effective and low-cost photodetectors. We investigated the parameters of the P3HT and PCBM layers for device performance and optimization. SCAPS-1D simulations were employed to optimize the thicknesses of the P3HT and PCBM layers, investigate the effects of shallow doping in the P3HT layer, and assess the influence of the back contact electrode’s work function on device performance. Furthermore, this study explored the impact of interface defect layer density on the characteristics of the device. Through systematic analyses, the optimal parameters for enhancing device responsivity were identified. The findings indicate that a P3HT layer thickness of 1200 nm, a PCBM layer thickness of 20 nm, and a back contact electrode with a work function of 4.9 eV achieve the highest responsivity. Notably, at a bias of −0.5 V, the responsivity exceeds 0.4 A/W within the wavelength range of 450 nm to 630 nm. These optimized parameters underscore the significant potential of the developed device as an organic photodetector, particularly for visible light detection. Full article
(This article belongs to the Special Issue Modeling, Simulation and Optimization of Nanomaterials)
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11 pages, 5814 KiB  
Article
Porous CuO Microspheres as Long-Lifespan Cathode Materials for Aqueous Zinc-Ion Batteries
by Yuqing Ai, Qiang Pang, Xinyu Liu, Fangyun Xin, Hong Wang, Mingming Xing, Yao Fu and Ying Tian
Nanomaterials 2024, 14(13), 1145; https://doi.org/10.3390/nano14131145 - 3 Jul 2024
Viewed by 637
Abstract
Cathode materials with conversion mechanisms for aqueous zinc-ion batteries (AZIBs) have shown a great potential as next-generation energy storage materials due to their high discharge capacity and high energy density. However, improving their cycling stability has been the biggest challenge plaguing researchers. In [...] Read more.
Cathode materials with conversion mechanisms for aqueous zinc-ion batteries (AZIBs) have shown a great potential as next-generation energy storage materials due to their high discharge capacity and high energy density. However, improving their cycling stability has been the biggest challenge plaguing researchers. In this study, CuO microspheres were prepared using a simple hydrothermal reaction, and the morphology and crystallinity of the samples were modulated by controlling the hydrothermal reaction time. The as-synthesized materials were used as cathode materials for AZIBs. The electrochemical experiments showed that the CuO-4h sample, undergoing a hydrothermal reaction for 4 h, had the longest lifecycle and the best rate of capability. A discharge capacity of 131.7 mAh g−1 was still available after 700 cycles at a current density of 500 mA g−1. At a high current density of 1.5 A g−1, the maintained capacity of the cell is 85.4 mA h g−1. The structural evolutions and valence changes in the CuO-4h cathode material were carefully explored by using ex situ XRD and ex situ XPS. CuO was reduced to Cu2O and Cu after the initial discharge, and Cu was oxidized to Cu2O instead of CuO during subsequent charging processes. We believe that these findings could introduce a novel approach to exploring high-performance cathode materials for AZIBs. Full article
(This article belongs to the Special Issue Application of Nanomaterials in Solid-State Energy Storage Materials and Batteries)
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23 pages, 11300 KiB  
Article
Vibration Analysis of Porous Cu-Si Microcantilever Beams in Fluids Based on Modified Couple Stress Theory
by Jize Jiang, Feixiang Tang, Siyu He, Fang Dong and Sheng Liu
Nanomaterials 2024, 14(13), 1144; https://doi.org/10.3390/nano14131144 - 3 Jul 2024
Viewed by 558
Abstract
The vibrations in functionally graded porous Cu-Si microcantilever beams are investigated based on physical neutral plane theory, modified coupled stress theory, and scale distribution theory (MCST&SDT). Porous microcantilever beams define four pore distributions. Considering the physical neutral plane theory, the material properties of [...] Read more.
The vibrations in functionally graded porous Cu-Si microcantilever beams are investigated based on physical neutral plane theory, modified coupled stress theory, and scale distribution theory (MCST&SDT). Porous microcantilever beams define four pore distributions. Considering the physical neutral plane theory, the material properties of the beams are computed through four different power-law distributions. The material properties of microcantilever beams are corrected by scale effects based on modified coupled stress theory. Considering the fluid driving force, the amplitude-frequency response spectra and resonant frequencies of the porous microcantilever beam in three different fluids are obtained based on the Euler–Bernoulli beam theory. The quality factors of porous microcantilever beams in three different fluids are derived by estimating the equation. The computational analysis shows that the presence of pores in microcantilever beams leads to a decrease in Young’s modulus. Different pore distributions affect the material properties to different degrees. The gain effect of the scale effect is weakened, but the one-dimensional temperature field and amplitude-frequency response spectra show an increasing trend. The quality factor is decreased by porosity, and the degree of influence of porosity increases as the beam thickness increases. The gradient factor n has a greater effect on the resonant frequency. The effect of porosity on the resonant frequency is negatively correlated when the gradient factor is small (n<1) but positively correlated when the gradient factor is large (n>1). Full article
(This article belongs to the Special Issue Theoretical Calculation Study of Nanomaterials: 2nd Edition)
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27 pages, 8622 KiB  
Article
Synthesis and Characterization of Silver-Modified Nanoporous Silica Materials for Enhanced Iodine Removal
by Ahmed Elmekawy, Qui Quach and Tarek M. Abdel-Fattah
Nanomaterials 2024, 14(13), 1143; https://doi.org/10.3390/nano14131143 - 3 Jul 2024
Viewed by 612
Abstract
In aquatic environments, the presence of iodine species, including radioactive isotopes like 129I and I2, poses significant environmental and health concerns. Iodine can enter water resources from various sources, including nuclear accidents, medical procedures, and natural occurrences. To address this [...] Read more.
In aquatic environments, the presence of iodine species, including radioactive isotopes like 129I and I2, poses significant environmental and health concerns. Iodine can enter water resources from various sources, including nuclear accidents, medical procedures, and natural occurrences. To address this issue, the use of natural occurring nanoporous minerals, such as zeolitic materials, for iodine removal will be explored. This study focuses on the adsorption of iodine by silver-modified zeolites (13X-Ag, 5A-Ag, Chabazite-Ag, and Clinoptilolite-Ag) and evaluates their performance under different conditions. All materials were characterized using scanning electron microscopey (SEM), energy-dispersive X-ray spectroscopy (EDS), powdered X-ray diffraction (P-XRD), Fourier-transform infrared spectrometry (FTIR), and nitrogen adsorption studies. The results indicate that Chabazite-Ag exhibited the highest iodine adsorption capacity, with an impressive 769 mg/g, making it a viable option for iodine removal applications. 13X-Ag and 5A-Ag also demonstrated substantial adsorption capacities of 714 mg/g and 556 mg/g, respectively, though their behavior varied according to different models. In contrast, Clinoptilolite-Ag exhibited strong pH-dependent behavior, rendering it less suitable for neutral to slightly acidic conditions. Furthermore, this study explored the impact of ionic strength on iodine adsorption, revealing that Chabazite-Ag is efficient in low-salinity environments with an iodine adsorption capacity of 51.80 mg/g but less effective in saline conditions. 5A-Ag proved to be a versatile option for various water treatments, maintaining its iodine adsorption capacity across different salinity levels. In contrast, Clinoptilolite-Ag exhibited high sensitivity to ionic competition, virtually losing its iodine adsorption ability at a NaCl concentration of 0.1 M. Kinetic studies indicated that the pseudo-second-order model best describes the adsorption process, suggesting chemisorption mechanisms dominate iodine removal. Chabazite-Ag exhibited the highest initial adsorption rate with a k2 value of 0.002 mg g−1 h−1, emphasizing its superior adsorption capabilities. Chabazite and Clinoptilolite, naturally occurring minerals, provide eco-friendly solutions for iodine adsorption. Chabazite superior iodine removal highlights its value in critical applications and its potential for addressing pressing environmental challenges. Full article
(This article belongs to the Special Issue Metallic Nanomaterial Applications in Selective Catalysis and Clean Energy)
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11 pages, 5185 KiB  
Article
Analysis of Fluorescent Carbon Nanodot Formation during Pretzel Production
by Dávid Semsey, Duyen H. H. Nguyen, Gréta Törős, Arjun Muthu, Safa Labidi, Hassan El-Ramady, Áron Béni, Mahendra Rai and Prokisch József
Nanomaterials 2024, 14(13), 1142; https://doi.org/10.3390/nano14131142 - 3 Jul 2024
Viewed by 595
Abstract
Baked pretzels are a popular choice for a quick snack, easily identifiable by their classic twisted shape, glossy exterior, and small salt crystals sprinkled on top, making them a standout snack. However, it is not commonly known that compounds with fluorescent properties can [...] Read more.
Baked pretzels are a popular choice for a quick snack, easily identifiable by their classic twisted shape, glossy exterior, and small salt crystals sprinkled on top, making them a standout snack. However, it is not commonly known that compounds with fluorescent properties can be formed during their production. Carbon nanodots (CNDs) with an average size of 3.5 nm were isolated and identified in bakery products. This study delved into the formation of CNDs in pretzel production using a fractional factorial experimental design. The research revealed that the baking temperature had the most significant impact on the concentration of CNDs, followed by the concentration of NaOH in the immersion solution, and then the baking time. This study highlights the unique role of the NaOH immersion step, which is not typically present in bread-making processes, in facilitating the formation of CNDs. This discovery highlights the strong correlation between the formation of CNDs and the heat treatment process. Monitoring and controlling these factors is crucial for regulating the concentration of CNDs in pretzel production and understanding nanoparticle formation in processed foods for food safety. Full article
(This article belongs to the Special Issue Nanomaterials and Nanostructures for Food Processing and Preservation)
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14 pages, 9321 KiB  
Article
One-Pot Synthesis of Cellulose-Based Carbon Aerogel Loaded with TiO2 and g-C3N4 and Its Photocatalytic Degradation of Rhodamine B
by Fangqin Liu, Mingjie Fan, Xia Liu and Jinyang Chen
Nanomaterials 2024, 14(13), 1141; https://doi.org/10.3390/nano14131141 - 2 Jul 2024
Viewed by 695
Abstract
A cellulose-based carbon aerogel (CTN) loaded with titanium dioxide (TiO2) and graphitic carbon nitride (g-C3N4) was prepared using sol–gel, freeze-drying, and high-temperature carbonization methods. The formation of the sol–gel was carried out through a one-pot method using [...] Read more.
A cellulose-based carbon aerogel (CTN) loaded with titanium dioxide (TiO2) and graphitic carbon nitride (g-C3N4) was prepared using sol–gel, freeze-drying, and high-temperature carbonization methods. The formation of the sol–gel was carried out through a one-pot method using refining papermaking pulp, tetrabutyl titanate, and urea as raw materials and hectorite as a cross-linking and reinforcing agent. Due to the cross-linking ability of hectorite, the carbonized aerogel maintained a porous structure and had a large specific surface area with low density (0.0209 g/cm3). The analysis of XRD, XPS, and Raman spectra revealed that the titanium dioxide (TiO2) and graphitic carbon nitride (g-C3N4) were uniformly distributed in the CTN, while TEM and SEM observations demonstrated the uniformly distributed three-dimensional porous structure of CTN. The photocatalytic activity of the CTN was determined according to its ability to degrade rhodamine B. The removal rate reached 89% under visible light after 120 min. In addition, the CTN was still stable after five reuse cycles. The proposed catalyst exhibits excellent photocatalytic performance under visible light conditions. Full article
(This article belongs to the Special Issue Nanoscale Material Catalysis for Environmental Protection)
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15 pages, 2843 KiB  
Article
p-Type Schottky Contacts for Graphene Adjustable-Barrier Phototransistors
by Carsten Strobel, Carlos Alvarado Chavarin, Martin Knaut, Matthias Albert, André Heinzig, Likhith Gummadi, Christian Wenger and Thomas Mikolajick
Nanomaterials 2024, 14(13), 1140; https://doi.org/10.3390/nano14131140 - 2 Jul 2024
Viewed by 687
Abstract
The graphene adjustable-barriers phototransistor is an attractive novel device for potential high speed and high responsivity dual-band photodetection. In this device, graphene is embedded between the semiconductors silicon and germanium. Both n-type and p-type Schottky contacts between graphene and the semiconductors are required [...] Read more.
The graphene adjustable-barriers phototransistor is an attractive novel device for potential high speed and high responsivity dual-band photodetection. In this device, graphene is embedded between the semiconductors silicon and germanium. Both n-type and p-type Schottky contacts between graphene and the semiconductors are required for this device. While n-type Schottky contacts are widely investigated, reports about p-type Schottky contacts between graphene and the two involved semiconductors are scarce. In this study, we demonstrate a p-type Schottky contact between graphene and p-germanium. A clear rectification with on–off ratios of close to 103 (±5 V) and a distinct photoresponse at telecommunication wavelengths in the infrared are achieved. Further, p-type silicon is transferred to or deposited on graphene, and we also observe rectification and photoresponse in the visible range for some of these p-type Schottky junctions. These results are an important step toward the realization of functional graphene adjustable-barrier phototransistors. Full article
(This article belongs to the Special Issue 2D Layered Nanomaterials and Heterostructures for Electronics, Optoelectronics and Sensing)
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3 pages, 172 KiB  
Editorial
Advanced Spintronic and Electronic Nanomaterials
by Gang Xiang and Hongtao Ren
Nanomaterials 2024, 14(13), 1139; https://doi.org/10.3390/nano14131139 - 2 Jul 2024
Viewed by 581
Abstract
Since single-layer graphene [...] Full article
(This article belongs to the Special Issue Advanced Spintronic and Electronic Nanomaterials)
14 pages, 3979 KiB  
Article
Influence of Polypyrrole on Phosphorus- and TiO2-Based Anode Nanomaterials for Li-Ion Batteries
by Chiwon Kang, Kibum Song, Seungho Ha, Yujin Sung, Yejin Kim, Keun-Young Shin and Byung Hyo Kim
Nanomaterials 2024, 14(13), 1138; https://doi.org/10.3390/nano14131138 - 2 Jul 2024
Viewed by 652
Abstract
Phosphorus (P) and TiO2 have been extensively studied as anode materials for lithium-ion batteries (LIBs) due to their high specific capacities. However, P is limited by low electrical conductivity and significant volume changes during charge and discharge cycles, while TiO2 is [...] Read more.
Phosphorus (P) and TiO2 have been extensively studied as anode materials for lithium-ion batteries (LIBs) due to their high specific capacities. However, P is limited by low electrical conductivity and significant volume changes during charge and discharge cycles, while TiO2 is hindered by low electrical conductivity and slow Li-ion diffusion. To address these issues, we synthesized organic–inorganic hybrid anode materials of P–polypyrrole (PPy) and TiO2–PPy, through in situ polymerization of pyrrole monomer in the presence of the nanoscale inorganic materials. These hybrid anode materials showed higher cycling stability and capacity compared to pure P and TiO2. The enhancements are attributed to the electrical conductivity and flexibility of PPy polymers, which improve the conductivity of the anode materials and effectively buffer volume changes to sustain structural integrity during the charge and discharge processes. Additionally, PPy can undergo polymerization to form multi-component composites for anode materials. In this study, we successfully synthesized a ternary composite anode material, P–TiO2–PPy, achieving a capacity of up to 1763 mAh/g over 1000 cycles. Full article
(This article belongs to the Special Issue Advanced Nanocomposites for Batteries and Supercapacitors)
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