Nanomaterials

13 pages, 6235 KiB

Open AccessFeature PaperArticle

Evaluation of the Photocatalytic Activity of Distinctive-Shaped ZnO Nanocrystals Synthesized Using Latex of Different Plants Native to the Amazon Rainforest

by Robert S. Matos, John M. Attah-Baah, Michael D. S. Monteiro, Benilde F. O. Costa, Marcelo A. Mâcedo, Simone P. A. Da Paz, Rômulo S. Angélica, Tiago M. de Souza, Ştefan Ţălu, Rosane M. P. B. Oliveira and Nilson S. Ferreira

Nanomaterials 2022, 12(16), 2889; https://doi.org/10.3390/nano12162889 - 22 Aug 2022

Cited by 10 | Viewed by 1843

Abstract

ZnO nanocrystals with three different morphologies have been synthesized via a simple sol-gel-based method using Brosimum parinarioides (bitter Amapá) and Parahancornia amapa (sweet Amapá) latex as chelating agents. X-ray diffraction (XRD) and electron diffraction patterns (SAED) patterns showed the ZnO nanocrystals were a [...] Read more.

ZnO nanocrystals with three different morphologies have been synthesized via a simple sol-gel-based method using Brosimum parinarioides (bitter Amapá) and Parahancornia amapa (sweet Amapá) latex as chelating agents. X-ray diffraction (XRD) and electron diffraction patterns (SAED) patterns showed the ZnO nanocrystals were a pure hexagonal wurtzite phase of ZnO. XRD-based spherical harmonics predictions and HRTEM images depicted that the nanocrystallites constitute pitanga-like (~15.8 nm), teetotum-like (~16.8 nm), and cambuci-like (~22.2 nm) shapes for the samples synthesized using bitter Amapá, sweet Amapá, and bitter/sweet Amapá chelating agent, respectively. The band gap luminescence was observed at ~2.67–2.79 eV along with several structural defect-related, blue emissions at 468–474 nm (V_O, V_Zn, Zn_i), green emissions positioned at 513.89–515.89 (h-

V_{O}^{+}

), and orange emission at 600.78 nm (

V_{O}^{+}

–

V_{O}^{+ +}

). The best MB dye removal efficiency (85%) was mainly ascribed to the unique shape and oxygen vacancy defects found in the teetotum-like ZnO nanocrystals. Thus, the bitter Amapá and sweet Amapá latex are effective chelating agents for synthesizing distinctive-shaped ZnO nanocrystals with highly defective and remarkable photocatalytic activity. Full article

(This article belongs to the Special Issue Nanomaterial Application in Environmental Monitoring and Water Treatment)

► Show Figures

Figure 1

16 pages, 6401 KiB

Open AccessArticle

The Transitional Wettability on Bamboo-Leaf-like Hierarchical-Structured Si Surface Fabricated by Microgrinding

by Ping Li, Jinxin Wang, Jiale Huang and Jianhua Xiang

Nanomaterials 2022, 12(16), 2888; https://doi.org/10.3390/nano12162888 - 22 Aug 2022

Cited by 3 | Viewed by 2193

Abstract

Stabilizing the hydrophobic wetting state on a surface is essential in heat transfer and microfluidics. However, most hydrophobic surfaces of Si are primarily achieved through microtexturing with subsequent coating or modification of low surface energy materials. The coatings make the hydrophobic surface unstable [...] Read more.

Stabilizing the hydrophobic wetting state on a surface is essential in heat transfer and microfluidics. However, most hydrophobic surfaces of Si are primarily achieved through microtexturing with subsequent coating or modification of low surface energy materials. The coatings make the hydrophobic surface unstable and impractical in many industrial applications. In this work, the Si chips’ wettability transitions are yielded from the original hydrophilic state to a stable transitional hydrophobic state by texturing bamboo-leaf-like hierarchical structures (BLHSs) through a diamond grinding wheel with one-step forming. Experiments showed that the contact angles (CAs) on the BLHS surfaces increased to 97° and only reduced by 2% after droplet impacts. This is unmatched by the current texturing surface without modification. Moreover, the droplets can be split up and transferred by the BLHS surfaces with their 100% mass. When the BLHS surfaces are modified by the low surface energy materials’ coating, the hydrophobic BLHS surfaces are upgraded to be superhydrophobic (CA > 135°). More interestingly, the droplet can be completely self-sucked into a hollow micro-tube within 0.1 s without applying external forces. A new wetting model for BLHS surfaces based on the fractal theory is determined by comparing simulated values with the measured static contact angle of the droplets. The successful preparation of the bamboo-leaf-like Si confirmed that transitional wettability surfaces could be achieved by the micromachining of grinding on the hard and brittle materials. Additionally, this may expand the application potential of the key semiconductor material of Si. Full article

(This article belongs to the Special Issue Heat Transfer in Nanocomposites: Theoretical Research and Application)

► Show Figures

Graphical abstract

15 pages, 2889 KiB

Open AccessArticle

Lindqvist@Nanoporous MOF-Based Catalyst for Effective Desulfurization of Fuels

by Simone Fernandes, Daniela Flores, Daniel Silva, Isabel Santos-Vieira, Fátima Mirante, Carlos M. Granadeiro and Salete S. Balula

Nanomaterials 2022, 12(16), 2887; https://doi.org/10.3390/nano12162887 - 22 Aug 2022

Cited by 10 | Viewed by 2294

Abstract

An effective and sustainable oxidative desulfurization process for treating a multicomponent model fuel was successfully developed using as a heterogeneous catalyst a composite material containing as an active center the europium Lindqvist [Eu(W₅O₁₈)₂]⁹⁻ (abbreviated as EuW [...] Read more.

An effective and sustainable oxidative desulfurization process for treating a multicomponent model fuel was successfully developed using as a heterogeneous catalyst a composite material containing as an active center the europium Lindqvist [Eu(W₅O₁₈)₂]⁹⁻ (abbreviated as EuW₁₀) encapsulated into the nanoporous ZIF-8 (zeolitic imidazolate framework) support. The EuW₁₀@ZIF-8 composite was obtained through an impregnation procedure, and its successful preparation was confirmed by various characterization techniques (FT-IR, XRD, SEM/EDS, ICP-OES). The catalytic activity of the composite and the isolated EuW₁₀ was evaluated in the desulfurization of a multicomponent model fuel containing dibenzothiophene derivatives (DBT, 4-MDBT and 4,6-DMDBT) with a total sulfur concentration of 1500 ppm. Oxidative desulfurization was performed using an ionic liquid as extraction solvent and aqueous hydrogen peroxide as oxidant. The catalytic results showed a remarkable desulfurization performance, with 99.5 and 94.7% sulfur removal in the first 180 min, for the homogeneous active center EuW₁₀ and the heterogeneous EuW₁₀@ZIF-8 catalysts, respectively. Furthermore, the stability of the nanocomposite catalyst was investigated by reusing and recycling processes. A superior retention of catalyst activity in consecutive desulfurization cycles was observed in the recycling studies when compared with the reusing experiments. Nevertheless, the nanostructure of ZIF-8 incorporating the active POM (polyoxometalate) was shown to be highly suitable for guaranteeing the absence of POM leaching, although structural modification was found for ZIF-8 after catalytic use that did not influenced catalytic performance. Full article

(This article belongs to the Special Issue Feature Papers in Nanomaterials Science)

► Show Figures

Figure 1

18 pages, 5630 KiB

Open AccessArticle

Development of Binder-Free Three-Dimensional Honeycomb-like Porous Ternary Layered Double Hydroxide-Embedded MXene Sheets for Bi-Functional Overall Water Splitting Reactions

by Sajjad Hussain, Dhanasekaran Vikraman, Ghazanfar Nazir, Muhammad Taqi Mehran, Faisal Shahzad, Khalid Mujasam Batoo, Hyun-Seok Kim and Jongwan Jung

Nanomaterials 2022, 12(16), 2886; https://doi.org/10.3390/nano12162886 - 22 Aug 2022

Cited by 19 | Viewed by 3138

Abstract

In this study, a honeycomb-like porous-structured nickel–iron–cobalt layered double hydroxide/Ti₃C₂T_x (NiFeCo–LDH@MXene) composite was successfully fabricated on a three-dimensional nickel foam using a simple hydrothermal approach. Owing to their distinguishable characteristics, the fabricated honeycomb porous-structured NiFeCo–LDH@MXene composites exhibited outstanding [...] Read more.

In this study, a honeycomb-like porous-structured nickel–iron–cobalt layered double hydroxide/Ti₃C₂T_x (NiFeCo–LDH@MXene) composite was successfully fabricated on a three-dimensional nickel foam using a simple hydrothermal approach. Owing to their distinguishable characteristics, the fabricated honeycomb porous-structured NiFeCo–LDH@MXene composites exhibited outstanding bifunctional electrocatalytic activity for pair hydrogen and oxygen evolution reactions in alkaline medium. The developed NiFeCo–LDH@MXene electrocatalyst required low overpotentials of 130 and 34 mV to attain a current density of 10 mA cm⁻² for OER and HER, respectively. Furthermore, an assembled NiFeCo–LDH@MXene‖NiFeCo–LDH@MXene device exhibited a cell voltage of 1.41 V for overall water splitting with a robust firmness for over 24 h to reach 10 mA cm⁻² current density, signifying outstanding performance for water splitting reactions. These results demonstrated the promising potential of the designed 3D porous NiFeCo–LDH@MXene sheets as outstanding candidates to replace future green energy conversion devices. Full article

(This article belongs to the Special Issue Hydrothermal Synthesis and Application of Nanomaterials)

► Show Figures

Figure 1

14 pages, 3369 KiB

Open AccessArticle

Construction of Prochloraz-Loaded Hollow Mesoporous Silica Nanoparticles Coated with Metal–Phenolic Networks for Precise Release and Improved Biosafety of Pesticides

by Liyin Shi, Qianwei Liang, Qikai Zang, Ze Lv, Xiaohan Meng and Jianguo Feng

Nanomaterials 2022, 12(16), 2885; https://doi.org/10.3390/nano12162885 - 22 Aug 2022

Cited by 21 | Viewed by 3039

Abstract

Currently, environmental-responsive pesticide delivery systems have become an essential way to improve the effective utilization of pesticides. In this paper, by using hollow mesoporous silica (HMS) as a nanocarrier and TA-Cu metal–phenolic networks as a capping agent, a pH-responsive controlled release nano-formulation loaded [...] Read more.

Currently, environmental-responsive pesticide delivery systems have become an essential way to improve the effective utilization of pesticides. In this paper, by using hollow mesoporous silica (HMS) as a nanocarrier and TA-Cu metal–phenolic networks as a capping agent, a pH-responsive controlled release nano-formulation loaded with prochloraz (Pro@HMS-TA-Cu) was constructed. The structure and properties of Pro@HMS-TA-Cu were adequately characterised and analysed. The results showed that the loading content of Pro@HMS-TA-Cu nanoparticles was about 17.7% and the Pro@HMS-TA-Cu nanoparticles exhibited significant pH-responsive properties. After a coating of the TA-Cu metal–phenolic network, the contact angle and adhesion work of Pro@HMS-TA-Cu nanoparticles on the surface of oilseed rape leaves after 360 s were 59.6° and 107.2 mJ·m⁻², respectively, indicating that the prepared nanoparticles possessed excellent adhesion. In addition, the Pro@HMS-TA-Cu nanoparticles demonstrated better antifungal activity against Sclerotinia sclerotiorum and lower toxicity to zebrafish compared to prochloraz technical. Hence, the pH-responsive nanoparticles prepared with a TA-Cu metal–phenolic network as a capping agent are highly efficient and environmentally friendly, providing a new approach for the development of new pesticide delivery systems. Full article

(This article belongs to the Special Issue Multifunction Nanoparticles and Nanopesticides in Agricultural Application)

► Show Figures

Graphical abstract

15 pages, 7711 KiB

Open AccessArticle

Effect of Silicate Additive on Structural and Electrical Properties of Germanium Nanowires Formed by Electrochemical Reduction from Aqueous Solutions

by Anna S. Eremina, Ilya M. Gavrilin, Nikolay S. Pokryshkin, Alexander Yu. Kharin, Alexander V. Syuy, Valentin S. Volkov, Valery G. Yakunin, Sergei S. Bubenov, Sergey G. Dorofeev, Sergey A. Gavrilov and Victor Yu. Timoshenko

Nanomaterials 2022, 12(16), 2884; https://doi.org/10.3390/nano12162884 - 22 Aug 2022

Viewed by 2230

Abstract

Layers of germanium (Ge) nanowires (NWs) on titanium foils were grown by metal-assisted electrochemical reduction of germanium oxide in aqueous electrolytes based on germanium oxide without and with addition of sodium silicate. Structural properties and composition of Ge NWs were studied by means [...] Read more.

Layers of germanium (Ge) nanowires (NWs) on titanium foils were grown by metal-assisted electrochemical reduction of germanium oxide in aqueous electrolytes based on germanium oxide without and with addition of sodium silicate. Structural properties and composition of Ge NWs were studied by means of the scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and Raman spectroscopy. When sodium silicate was added to the electrolyte, Ge NWs consisted of 1–2 at.% of silicon (Si) and exhibited smaller mean diameter and improved crystallinity. Additionally, samples of Ge NW films were prepared by ultrasonic removal of Ge NWs from titanium foils followed with redeposition on corundum substrates with platinum electrodes. The electrical conductivity of Ge NW films was studied at different temperatures from 25 to 300 °C and an effect of the silicon impurity on the thermally activated electrical conductivity was revealed. Furthermore, the electrical conductivity of Ge NW films on corundum substrates exhibited a strong sensor response on the presence of saturated vapors of different liquids (water, acetone, ethanol, and isopropanol) in air and the response was dependent on the presence of Si impurities in the nanowires. The results obtained indicate the possibility of controlling the structure and electrical properties of Ge NWs by introducing silicate additives during their formation, which is of interest for applications in printed electronics and molecular sensorics. Full article

(This article belongs to the Special Issue Nanomaterials for Electron Devices)

► Show Figures

Graphical abstract

12 pages, 2558 KiB

Open AccessArticle

Realization of Multifunctional Metamaterial Structure Based on the Combination of Vanadium Dioxide and Graphene

by Mingxuan Cao, Junchao Wang, Matthew M. F. Yuen and Dexian Yan

Nanomaterials 2022, 12(16), 2883; https://doi.org/10.3390/nano12162883 - 22 Aug 2022

Cited by 5 | Viewed by 2008

Abstract

Combining tunable properties and various functionalities into a single metamaterial structure has become a novel research hotspot and can be used to tackle great challenges. The multifunctional metamaterial structure that combines absorption, linear-to-circular (LTC) polarization conversion, filtering and switching functions into a single [...] Read more.

Combining tunable properties and various functionalities into a single metamaterial structure has become a novel research hotspot and can be used to tackle great challenges. The multifunctional metamaterial structure that combines absorption, linear-to-circular (LTC) polarization conversion, filtering and switching functions into a single metamaterial device was designed and investigated in this study. The switching of different functions can be achieved based on the phase transition of vanadium dioxide (VO₂) and change of graphene chemical potential. When VO₂ is in a metal state, the multi-frequency absorption and LTC polarization conversion can be achieved with different chemical potentials. When VO₂ is in the insulator state and the polarization angle of incident wave is 45°, the device can be used to select or isolate the incident waves with different polarization states in the frequency region of 1.2–1.8 THz. Furthermore, when the chemical potentials are 0.05 eV and 1.2 eV, the corresponding transmissions of the TE-polarized wave demonstrate the opposite results, realizing the switching functions in the frequency region of 0.88–1.34 THz. In the frequency region above 2 THz, the multi-frequency rejection filter can be achieved. The designed switchable multifunctional metamaterial device can be widely implemented in radar monitoring and communication systems. Full article

(This article belongs to the Special Issue Nanophotonics and Optoelectronic Devices)

► Show Figures

Figure 1

9 pages, 1774 KiB

Open AccessCommunication

Uncovering the Role of Surface-Attached Ag Nanoparticles in Photodegradation Improvement of Rhodamine B by ZnO-Ag Nanorods

by Svetlana Em, Mussa Yedigenov, Laura Khamkhash, Shanazar Atabaev, Anara Molkenova, Stavros G. Poulopoulos and Timur Sh. Atabaev

Nanomaterials 2022, 12(16), 2882; https://doi.org/10.3390/nano12162882 - 22 Aug 2022

Cited by 9 | Viewed by 2036

Abstract

ZnO nanorods decorated with metal nanoparticles have sparked considerable interest in recent years thanks to their suitability for a wide range of applications, such as photocatalysis, photovoltaics, antibacterial activity, and sensing devices. In this study, we prepared and investigated the improved solar-light-assisted photocatalytic [...] Read more.

ZnO nanorods decorated with metal nanoparticles have sparked considerable interest in recent years thanks to their suitability for a wide range of applications, such as photocatalysis, photovoltaics, antibacterial activity, and sensing devices. In this study, we prepared and investigated the improved solar-light-assisted photocatalytic activity of ZnO nanorods (NRs) decorated with Ag nanoparticles (NPs) using a conventional rhodamine B (RB) dye as a model water pollutant. We showed that the presence of Ag NPs on the surface of ZnO NRs significantly increases the degradation rate of RB dye (~0.2432 min⁻¹) when compared to bare ZnO NRs (~0.0431 min⁻¹). The improved photocatalytic activity of ZnO-Ag was further experimentally tested using radical scavengers. The obtained results reveal that ˙OH and ˙O₂⁻ radicals are main active species involved in the RB dye photodegradation by ZnO-Ag NRs. It was concluded that efficient charge separation plays a major role in photocatalytic activity improvement. Full article

(This article belongs to the Collection Metallic and Metal Oxide Nanohybrids and Their Applications)

► Show Figures

Figure 1

9 pages, 2958 KiB

Open AccessArticle

Study on the Electrical Conduction Mechanism of Unipolar Resistive Switching Prussian White Thin Films

by Lindiomar B. Avila, Pablo C. Serrano Arambulo, Adriana Dantas, Edy E. Cuevas-Arizaca, Dinesh Kumar and Christian K. Müller

Nanomaterials 2022, 12(16), 2881; https://doi.org/10.3390/nano12162881 - 22 Aug 2022

Cited by 7 | Viewed by 2200

Abstract

The electrical conduction mechanism of resistive switching Prussian white (PW) thin films obtained by the electrodeposition method was examined by AC impedance spectroscopy and DC current–voltage measurements. Using an electrode tip to contact PW grown over Au, robust unipolar resistive switching was observed [...] Read more.

The electrical conduction mechanism of resistive switching Prussian white (PW) thin films obtained by the electrodeposition method was examined by AC impedance spectroscopy and DC current–voltage measurements. Using an electrode tip to contact PW grown over Au, robust unipolar resistive switching was observed with a current change of up to three orders of magnitude, high repeatability, and reproducibility. Moreover, electrical impedance spectroscopy showed that the resistive switching comes from small conductive filaments formed by potassium ions before the establishment of larger conductive channels. Both voltammetry and EIS measurements suggest that the electrical properties and conductive filament formation are influenced by defects and ions present in the grain boundaries. Thus, PW is a potential material for the next generation of ReRAM devices. Full article

(This article belongs to the Section Nanoelectronics, Nanosensors and Devices)

► Show Figures

Graphical abstract

11 pages, 4927 KiB

Open AccessArticle

Water-Induced Nanometer-Thin Crystalline Indium-Praseodymium Oxide Channel Layers for Thin-Film Transistors

by Wangying Xu, Chuyu Xu, Zhibo Zhang, Weicheng Huang, Qiubao Lin, Shuangmu Zhuo, Fang Xu, Xinke Liu, Deliang Zhu and Chun Zhao

Nanomaterials 2022, 12(16), 2880; https://doi.org/10.3390/nano12162880 - 22 Aug 2022

Cited by 4 | Viewed by 1845

Abstract

We report water-induced nanometer-thin crystalline indium praseodymium oxide (In-Pr-O) thin-film transistors (TFTs) for the first time. This aqueous route enables the formation of dense ultrathin (~6 nm) In-Pr-O thin films with near-atomic smoothness (~0.2 nm). The role of Pr doping is investigated by [...] Read more.

We report water-induced nanometer-thin crystalline indium praseodymium oxide (In-Pr-O) thin-film transistors (TFTs) for the first time. This aqueous route enables the formation of dense ultrathin (~6 nm) In-Pr-O thin films with near-atomic smoothness (~0.2 nm). The role of Pr doping is investigated by a battery of experimental techniques. It is revealed that as the Pr doping ratio increases from 0 to 10%, the oxygen vacancy-related defects could be greatly suppressed, leading to the improvement of TFT device characteristics and durability. The optimized In-Pr-O TFT demonstrates state-of-the-art electrical performance with mobility of 17.03 ± 1.19 cm²/Vs and on/off current ratio of ~10⁶ based on Si/SiO₂ substrate. This achievement is due to the low electronegativity and standard electrode potential of Pr, the high bond strength of Pr-O, same bixbyite structure of Pr₂O₃ and In₂O₃, and In-Pr-O channel’s nanometer-thin and ultrasmooth nature. Therefore, the designed In-Pr-O channel holds great promise for next-generation transistors. Full article

(This article belongs to the Special Issue Innovative Semiconducting Materials Technology toward New-Generation Hardware Applications)

► Show Figures

Figure 1

16 pages, 5393 KiB

Open AccessArticle

Hydrothermal Synthesis of Co-Exposed-Faceted WO₃ Nanocrystals with Enhanced Photocatalytic Performance

by Xianjun Niu, Yien Du, Jing He, Xiaodong Li and Guangming Wen

Nanomaterials 2022, 12(16), 2879; https://doi.org/10.3390/nano12162879 - 22 Aug 2022

Cited by 5 | Viewed by 1945

Abstract

In this paper, rod-shaped, cuboid-shaped, and irregular WO₃ nanocrystals with different co-exposed crystal facets were prepared for the first time by a simple hydrothermal treatment of tungstic acid colloidal suspension with desired pH values. The crystal structure, morphology, specific surface area, pore [...] Read more.

In this paper, rod-shaped, cuboid-shaped, and irregular WO₃ nanocrystals with different co-exposed crystal facets were prepared for the first time by a simple hydrothermal treatment of tungstic acid colloidal suspension with desired pH values. The crystal structure, morphology, specific surface area, pore size distribution, chemical composition, electronic states of the elements, optical properties, and charge migration behavior of as-obtained WO₃ products were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), fully automatic specific surface area and porosity analyzer, UV–vis absorption spectra, photoluminescence (PL) spectra, and electrochemical impedance spectroscopy (EIS). The photocatalytic performances of the synthesized pHx-WO₃ nanocrystals (x = 0.0, 1.5, 3.0, 5.0, and 7.0) were evaluated and compared with the commercial WO₃ (CM-WO₃) nanocrystals. The pH7.0-WO₃ nanocrystals with co-exposed {202} and {020} facets exhibited highest photocatalytic activity for the degradation of methylene blue solution, which can be attributed to the synergistic effects of the largest specific surface area, the weakest luminescence peak intensity and the smallest arc radius diameter. Full article

(This article belongs to the Section Synthesis, Interfaces and Nanostructures)

► Show Figures

Figure 1

13 pages, 5517 KiB

Open AccessEditor’s ChoiceArticle

Multifunctional Carbon Nanotubes-Reinforced Surlyn Nanocomposites: A Study of Strain-Sensing and Self-Healing Capabilities

by Antonio del Bosque, Rocío Calderón-Villajos, María Sánchez and Alejandro Ureña

Nanomaterials 2022, 12(16), 2878; https://doi.org/10.3390/nano12162878 - 21 Aug 2022

Cited by 4 | Viewed by 2401

Abstract

Multifunctional nanocomposites based on carbon nanotubes (CNT)-reinforced Surlyn, which is a commercial ionomeric polymer, are manufactured by micro-compounding and hot-press processes. Multifunctionality is studied in terms of electromechanical response and self-healing abilities. The strain sensing analysis under tensile conditions shows ultra-high gauge factor [...] Read more.

Multifunctional nanocomposites based on carbon nanotubes (CNT)-reinforced Surlyn, which is a commercial ionomeric polymer, are manufactured by micro-compounding and hot-press processes. Multifunctionality is studied in terms of electromechanical response and self-healing abilities. The strain sensing analysis under tensile conditions shows ultra-high gauge factor (GF) values from 10 to 20 at low strain levels up to 10⁶ at high strain levels, and a decreasing sensitivity as CNT content increases because of the reduction in the tunneling distance between neighboring nanoparticles. The electromechanical response under consecutive tensile cycles demonstrated the robustness of the proposed materials due to the repeatability of both responses. With regard to mechanical properties, the addition of CNT induces a clear increase in Young’s modulus because the nanoparticles enable uniform load distributions. Moreover, self-healing capabilities are improved when 4 and 5 wt.% CNT are introduced because of the synergistic effect of the high thermal conductivity of CNT and their homogeneous distribution, promoting an increase in the thermal conductivity of bulk nanocomposites. Thus, by comparing the measured functionalities, 4 and 5 wt.% CNT-reinforced Surlyn nanocomposites showed a high potential for various applications due to their high degree of multifunctionality. Full article

(This article belongs to the Special Issue Nanostructures for Surfaces, Catalysis and Sensing)

► Show Figures

Figure 1

13 pages, 11706 KiB

Open AccessArticle

Influence of Soft Phase and Carbon Nanotube Content on the Properties of Hierarchical AZ61 Matrix Composite with Isolated Soft Phase

by Yunpeng Ding, Sijia Jiao, Yizhuang Zhang, Zhiai Shi, Jinbiao Hu, Xulei Wang, Zhiyuan Li, Hanying Wang and Xiaoqin Guo

Nanomaterials 2022, 12(16), 2877; https://doi.org/10.3390/nano12162877 - 21 Aug 2022

Cited by 4 | Viewed by 1752

Abstract

Carbon nanotube-reinforced magnesium matrix (CNTs/Mg) composite has great application potential in the transportation industry, but the trade-off between strength and ductility inhibits its widespread application. In order to balance the strength and plasticity of the composite, in this work, on the basis of [...] Read more.

Carbon nanotube-reinforced magnesium matrix (CNTs/Mg) composite has great application potential in the transportation industry, but the trade-off between strength and ductility inhibits its widespread application. In order to balance the strength and plasticity of the composite, in this work, on the basis of the AZ61 matrix composite homogeneously reinforced by Ni-coated CNTs (hard phase), 30 vol.% large-size AZ61 particles are introduced as an isolated soft phase to fabricate hierarchical CNTs/AZ61 composites. The compression tests show the fracture strain and compressive strength of this composite increases by 54% and 8%, respectively, compared with homogeneous CNTs/AZ61 composite. During deformation, the hard phase is mainly responsible for bearing the load and bringing high strength, due to the precipitation of the Mg₁₇Al₁₂ phase, uniformly dispersed CNT and strong interfacial bonding of the CNTs/Mg interface through nickel plating and interfacial chemical reaction. Furthermore, the toughening of the soft phase results in high ductility. With the increase in CNT content, the compressive strength of composites is nearly unchanged but the fracture strain gradually decreases due to the stress concentration of CNT and its agglomeration. Full article

(This article belongs to the Special Issue Advanced Carbon Nanostructures: Synthesis, Properties and Applications)

► Show Figures

Figure 1

12 pages, 6119 KiB

Open AccessArticle

In Situ Formation of CoS₂ Hollow Nanoboxes via Ion-Exchange for High-Performance Microwave Absorption

by Dongwei Xu, Huanhuan Guo, Feifan Zhang, Yanmei Wu, Xiaoqin Guo, Yumei Ren and Desheng Feng

Nanomaterials 2022, 12(16), 2876; https://doi.org/10.3390/nano12162876 - 21 Aug 2022

Cited by 7 | Viewed by 1891

Abstract

Hollow nanoboxes structure have raised great attention as microwave absorption materials on account of their ultralow density and large specific area. By introducing an adjustable interior cavity structure, the dielectric loss and microwave absorption performance were affected by the tunable complex permittivity and [...] Read more.

Hollow nanoboxes structure have raised great attention as microwave absorption materials on account of their ultralow density and large specific area. By introducing an adjustable interior cavity structure, the dielectric loss and microwave absorption performance were affected by the tunable complex permittivity and impedance matching was improved. In our study, hollow CoS₂ nanoboxes with designable interspaces were successfully fabricated based on the surfactant-assisted solution method and followed by an in situ ion-exchange process. The structure, elemental compositions and morphology of the products were characterized by XRD, XPS, EDX, SEM and TEM, respectively. In addition, microwave absorption performance and the intrinsic mechanism are investigated in-depth. The paraffin-based composites with 20 wt.% filling contents exhibited superior microwave absorption capacities in view of both maximum reflection loss value (RLmax, −54.48 dB) and effective absorption bandwidth (EAB, below −10 dB, 6.0 GHz), which can be ascribed to unique hollow structure and good impedance matching. With these considerations in mind, this study provides a reference for the construction of high-performance microwave absorbers with unique hollow structure. Full article

(This article belongs to the Special Issue New Insights into Two-Dimensional (2D) Transition Metal Materials)

► Show Figures

Figure 1

11 pages, 2146 KiB

Open AccessArticle

High-Value Utilization of Silicon Cutting Waste and Excrementum Bombycis to Synthesize Silicon–Carbon Composites as Anode Materials for Li-Ion Batteries

by Hengsong Ji, Jun Li, Sheng Li, Yingxue Cui, Zhijin Liu, Minggang Huang, Chun Xu, Guochun Li, Yan Zhao and Huaming Li

Nanomaterials 2022, 12(16), 2875; https://doi.org/10.3390/nano12162875 - 21 Aug 2022

Cited by 11 | Viewed by 2258

Abstract

Silicon-based photovoltaic technology is helpful in reducing the cost of power generation; however, it suffers from economic losses and environmental pollution caused by silicon cutting waste. Herein, a hydrothermal method accompanied by heat treatment is proposed to take full advantage of the photovoltaic [...] Read more.

Silicon-based photovoltaic technology is helpful in reducing the cost of power generation; however, it suffers from economic losses and environmental pollution caused by silicon cutting waste. Herein, a hydrothermal method accompanied by heat treatment is proposed to take full advantage of the photovoltaic silicon cutting waste and biomass excrementum bombycis to fabricate flake-like porous Si@C (FP-Si@C) composite anodes for lithium-ion batteries (LIBs). The resulting FP-Si@C composite with a meso-macroporous structure can buffer the severe volume changes and facilitate electrolyte penetration. Meanwhile, the slightly graphitic carbon with high electrical conductivity and mechanical strength tightly surrounds the Si nanoflakes, which not only contributes to the ion/electron transport but also maintains the electrode structural integrity during the repeated lithiation/delithiation process. Accordingly, the synergistic effect of the unique structure of FP-Si@C composite contributes to a high discharge specific capacity of 1322 mAh g⁻¹ at 0.1 A g⁻¹, superior cycle stability with a capacity retention of 70.8% after 100 cycles, and excellent rate performance with a reversible capacity of 406 mAh g⁻¹ at 1.0 A g⁻¹. This work provides an easy and cost-effective approach to achieving the high-value application of photovoltaic silicon cutting waste, as well as obtaining high-performance Si-based anodes for LIBs. Full article

(This article belongs to the Special Issue Advanced Functional Nanomaterials for Efficient Energy Conversion and Storage)

► Show Figures

Figure 1

25 pages, 7100 KiB

Open AccessEditor’s ChoiceReview

Composition and Structure Progress of the Catalytic Interface Layer for Bipolar Membrane

by Di Zhao, Jinyun Xu, Yu Sun, Minjing Li, Guoqiang Zhong, Xudong Hu, Jiefang Sun, Xiaoyun Li, Han Su, Ming Li, Ziqi Zhang, Yu Zhang, Liping Zhao, Chunming Zheng and Xiaohong Sun

Nanomaterials 2022, 12(16), 2874; https://doi.org/10.3390/nano12162874 - 21 Aug 2022

Cited by 5 | Viewed by 3446

Abstract

Bipolar membranes, a new type of composite ion exchange membrane, contain an anion exchange layer, a cation exchange layer and an interface layer. The interface layer or junction is the connection between the anion and cation exchange layers. Water is dissociated into protons [...] Read more.

Bipolar membranes, a new type of composite ion exchange membrane, contain an anion exchange layer, a cation exchange layer and an interface layer. The interface layer or junction is the connection between the anion and cation exchange layers. Water is dissociated into protons and hydroxide ions at the junction, which provides solutions to many challenges in the chemical, environmental and energy fields. By combining bipolar membranes with electrodialysis technology, acids and bases could be produced with low cost and high efficiency. The interface layer or junction of bipolar membranes (BPMs) is the connection between the anion and cation exchange layers, which the membrane and interface layer modification are vital for improving the performance of BPMs. This paper reviews the effect of modification of a bipolar membrane interface layer on water dissociation efficiency and voltage across the membrane, which divides into three aspects: organic materials, inorganic materials and newly designed materials with multiple components. The structure of the interface layer is also introduced on the performance of bipolar membranes. In addition, the remainder of this review discusses the challenges and opportunities for the development of more efficient, sustainable and practical bipolar membranes. Full article

(This article belongs to the Special Issue Nanoporous Materials for Electrochemical Charge Transfer and Electrocatalysis)

► Show Figures

Figure 1

17 pages, 2452 KiB

Open AccessReview

Recent Advances in the Seed-Directed Synthesis of Zeolites without Addition of Organic Templates

by Shujie Dai, Yichang Yang, Jinghuai Yang, Shichang Chen and Longfeng Zhu

Nanomaterials 2022, 12(16), 2873; https://doi.org/10.3390/nano12162873 - 21 Aug 2022

Cited by 5 | Viewed by 2864

Abstract

Zeolites have been widely employed in fields of petroleum refining, fine chemicals and environmental protection, but their syntheses are always performed in the presence of organic templates, which have many drawbacks such as high cost and polluted wastes. In recent years, the seed-directed [...] Read more.

Zeolites have been widely employed in fields of petroleum refining, fine chemicals and environmental protection, but their syntheses are always performed in the presence of organic templates, which have many drawbacks such as high cost and polluted wastes. In recent years, the seed-directed synthesis of zeolites has been paid much attention due to its low-cost and environmentally friendly features. In this review, the seed-directed synthesis of Al-rich zeolites with homonuclear and heteronuclear features, the seed-directed synthesis of Si-rich zeolites assisted with ethanol and the utility of seed-directed synthesis have been summarized. This review could help zeolite researchers understand the recent progress of seed-directed synthesis. Full article

(This article belongs to the Special Issue Current Review in Synthesis, Interfaces, and Nanostructures)

► Show Figures

Figure 1

18 pages, 5127 KiB

Open AccessFeature PaperArticle

Impact of Ga³⁺ Ions on the Structure, Magnetic, and Optical Features of Co-Ni Nanostructured Spinel Ferrite Microspheres

by Munirah A. Almessiere, Yassine Slimani, Sadaqat Ali, Abdulhadi Baykal, Rabindran Jermy Balasamy, Sadik Guner, İsmail A. Auwal, Alex V. Trukhanov, Sergei V. Trukhanov and Ayyar Manikandan

Nanomaterials 2022, 12(16), 2872; https://doi.org/10.3390/nano12162872 - 21 Aug 2022

Cited by 27 | Viewed by 2411

Abstract

Co-Ni ferrite is one of the crucial materials for the electronic industry. A partial substitution with a rare-earth metal brings about modification in crystal lattice and broadens knowledge in the discovery of new magnetic material. Current work reports a Ga³⁺ substitution in [...] Read more.

Co-Ni ferrite is one of the crucial materials for the electronic industry. A partial substitution with a rare-earth metal brings about modification in crystal lattice and broadens knowledge in the discovery of new magnetic material. Current work reports a Ga³⁺ substitution in the Co-Ni ferrite with composition Co_0.5Ni_0.5Fe_2−xGa_xO₄ (where x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0), herein referred to as spinel ferrite microspheres (CoNiGa-SFMCs). The samples were crystallized hydrothermally showing a hollow sphere morphology. The crystal phase, magnetic, morphology, and optical behaviour were examined using various microscopy and spectroscopic tools. While the XRD confirmed the phase of SFMCs, the crystallite size varied between 9 and 12 nm. The Tauc plot obtained from DRS (diffuse reflectance spectroscopy) shows the direct optical energy bandgap (E_g) of the products, with the pristine reading having the value of 1.41 eV E_g; the band gap increased almost linearly up to 1.62 eV along with rising the Ga³⁺ amount. The magnetic features, on the other hand, indicated the decrease in coercivity (H_c) as more Ga³⁺ is introduced. Moreover, there was a gradual increase in both saturation magnetization (M_s) and magnetic moment (

n_{B}

) with increasing amount of Ga³⁺ till x = 0.6 and then a progressive decline with increases in the x content; this was ascribed to the spin-glass-like behavior at low temperatures. It was detected that magnetic properties correlate well with crystallite/particle size, cation distribution, and anisotropy. Full article

(This article belongs to the Special Issue Ferromagnetic, Ferroelectric, and Multiferroic Oxide Nanopowders, Nanoceramics, and Thin Films)

► Show Figures

Figure 1

16 pages, 32169 KiB

Open AccessArticle

Defect- and Interface-Induced Dielectric Loss in ZnFe₂O₄/ZnO/C Electromagnetic Wave Absorber

by Hao Shen, Zhen Wang, Chun Wang, Pengfei Zou, Zhaoyang Hou, Chunlong Xu and Hongjing Wu

Nanomaterials 2022, 12(16), 2871; https://doi.org/10.3390/nano12162871 - 20 Aug 2022

Cited by 11 | Viewed by 2031

Abstract

Controlling defects and interfaces in composite absorbers can effectively regulate electromagnetic (EM) parameters and enhance the electromagnetic wave (EMW) absorption ability, but the mechanism still needs to be further elucidated. In this study, ZnFe₂O₄/ZnO/C composite was synthesized via the [...] Read more.

Controlling defects and interfaces in composite absorbers can effectively regulate electromagnetic (EM) parameters and enhance the electromagnetic wave (EMW) absorption ability, but the mechanism still needs to be further elucidated. In this study, ZnFe₂O₄/ZnO/C composite was synthesized via the hydrothermal method followed by post-annealing in different atmospheres. Defects and interfaces were characterized by Raman, PL spectroscopy, XPS and TEM, and their relationship with dielectric loss and EMW absorption performance was discussed in detail. Results show that the N₂-annealed ZnFe₂O₄/ZnO/C composite with abundant defects and interfaces as well as an optimized composition exhibits excellent EMW dissipation ability, with a RL_min value of −17.4 dB and an f_e of 3.85 GHz at a thickness of 2.28 mm. The excellent EMW absorption performance originates from suitable impedance matching, significant conduction loss and strong dielectric loss (interfacial polarization, diploe polarization and defect polarization) dominated by lattice defects and interfaces. This study provides a view into the relationship between defects, interfaces, EM parameters and EMW absorption ability, and also suggests an effective way to promote EMW dissipation ability of the absorbers by controlling defects and interfaces. Full article

(This article belongs to the Special Issue State-of-the-Art Electromagnetic Wave Absorbing Nanocomposites in Asia)

► Show Figures

Graphical abstract

16 pages, 6081 KiB

Open AccessArticle

Surface, Structural, and Mechanical Properties Enhancement of Cr₂O₃ and SiO₂ Co-Deposited Coatings with W or Be

by Mihail Lungu, Daniel Cristea, Flaviu Baiasu, Cornel Staicu, Alexandru Marin, Oana Gloria Pompilian, Bogdan Butoi, Claudiu Locovei and Corneliu Porosnicu

Nanomaterials 2022, 12(16), 2870; https://doi.org/10.3390/nano12162870 - 20 Aug 2022

Cited by 1 | Viewed by 2146

Abstract

Direct current (DC) and radio frequency (RF) magnetron sputtering methods were selected for conducting the deposition of structural materials, namely ceramic and metallic co-depositions. A total of six configurations were deposited: single thin layers of oxides (Cr₂O₃, SiO₂ [...] Read more.

Direct current (DC) and radio frequency (RF) magnetron sputtering methods were selected for conducting the deposition of structural materials, namely ceramic and metallic co-depositions. A total of six configurations were deposited: single thin layers of oxides (Cr₂O₃, SiO₂) and co-deposition configurations (50:50 wt.%) as structural materials (W, Be)—(Cr₂O₃, SiO₂), all deposited on 304L stainless steel (SS). A comprehensive evaluation such as surface topology, thermal desorption outgassing, and structural/chemical state was performed. Moreover, mechanical characterization evaluating properties such as adherence, nano indentation hardness, indentation modulus, and deformation relative to yielding, was performed. Experimental results show that, contrary to SiO₂ matrix, the composite layers of Cr₂O₃ with Be and W exhibit surface smoothing with mitigation of artifacts, thus presenting a uniform and compact state with the best microstructure. These results are relevant in order to develop future dense coatings to be used in the fusion domain. Full article

► Show Figures

Figure 1

9 pages, 1373 KiB

Open AccessArticle

Albumin Stabilized Fe@C Core–Shell Nanoparticles as Candidates for Magnetic Hyperthermia Therapy

by Maria Antonieta Ramírez-Morales, Anastasia E. Goldt, Polina M. Kalachikova, Javier A. Ramirez B., Masashi Suzuki, Alexey N. Zhigach, Asma Ben Salah, Liliya I. Shurygina, Sergey D. Shandakov, Timofei Zatsepin, Dmitry V. Krasnikov, Toru Maekawa, Evgeny N. Nikolaev and Albert G. Nasibulin

Nanomaterials 2022, 12(16), 2869; https://doi.org/10.3390/nano12162869 - 20 Aug 2022

Cited by 3 | Viewed by 2845

Abstract

Carbon-encapsulated iron nanoparticles (Fe@C) with a mean diameter of 15 nm have been synthesized using evaporation–condensation flow–levitation method by the direct iron-carbon gas-phase reaction at high temperatures. Further, Fe@C were stabilized with bovine serum albumin (BSA) coating, and their electromagnetic properties were evaluated [...] Read more.

Carbon-encapsulated iron nanoparticles (Fe@C) with a mean diameter of 15 nm have been synthesized using evaporation–condensation flow–levitation method by the direct iron-carbon gas-phase reaction at high temperatures. Further, Fe@C were stabilized with bovine serum albumin (BSA) coating, and their electromagnetic properties were evaluated to test their performance in magnetic hyperthermia therapy (MHT) through a specific absorption rate (SAR). Heat generation was observed at different Fe@C concentrations (1, 2.5, and 5 mg/mL) when applied 331 kHz and 60 kA/m of an alternating magnetic field, resulting in SAR values of 437.64, 129.36, and 50.4 W/g for each concentration, respectively. Having such high SAR values at low concentrations, obtained material is ideal for use in MHT. Full article

(This article belongs to the Section Synthesis, Interfaces and Nanostructures)

► Show Figures

Figure 1

17 pages, 24329 KiB

Open AccessArticle

An Optical Modeling Framework for Coronavirus Detection Using Graphene-Based Nanosensor

by Amir Maghoul, Ingve Simonsen, Ali Rostami and Peyman Mirtaheri

Nanomaterials 2022, 12(16), 2868; https://doi.org/10.3390/nano12162868 - 20 Aug 2022

Cited by 4 | Viewed by 3122

Abstract

The outbreak of the COVID-19 virus has faced the world with a new and dangerous challenge due to its contagious nature. Hence, developing sensory technologies to detect the coronavirus rapidly can provide a favorable condition for pandemic control of dangerous diseases. In between, [...] Read more.

The outbreak of the COVID-19 virus has faced the world with a new and dangerous challenge due to its contagious nature. Hence, developing sensory technologies to detect the coronavirus rapidly can provide a favorable condition for pandemic control of dangerous diseases. In between, because of the nanoscale size of this virus, there is a need for a good understanding of its optical behavior, which can give an extraordinary insight into the more efficient design of sensory devices. For the first time, this paper presents an optical modeling framework for a COVID-19 particle in the blood and extracts its optical characteristics based on numerical computations. To this end, a theoretical foundation of a COVID-19 particle is proposed based on the most recent experimental results available in the literature to simulate the optical behavior of the coronavirus under varying physical conditions. In order to obtain the optical properties of the COVID-19 model, the light reflectance by the structure is then simulated for different geometrical sizes, including the diameter of the COVID-19 particle and the size of the spikes surrounding it. It is found that the reflectance spectra are very sensitive to geometric changes of the coronavirus. Furthermore, the density of COVID-19 particles is investigated when the light is incident on different sides of the sample. Following this, we propose a nanosensor based on graphene, silicon, and gold nanodisks and demonstrate the functionality of the designed devices for detecting COVID-19 particles inside the blood samples. Indeed, the presented nanosensor design can be promoted as a practical procedure for creating nanoelectronic kits and wearable devices with considerable potential for fast virus detection. Full article

(This article belongs to the Special Issue Graphene Sensors)

► Show Figures

Figure 1

16 pages, 3014 KiB

Open AccessEditor’s ChoiceArticle

Influence of Asphaltene Modification on Structure of P3HT/Asphaltene Blends: Molecular Dynamics Simulations

by Natalia Borzdun, Artyom Glova, Sergey Larin and Sergey Lyulin

Nanomaterials 2022, 12(16), 2867; https://doi.org/10.3390/nano12162867 - 20 Aug 2022

Cited by 2 | Viewed by 1915

Abstract

Further development and commercialization of bulk heterojunction (BHJ) solar cells require the search for novel low-cost materials. The present study addresses the relations between the asphaltenes’ chemical structure and the morphology of the poly(3-hexylthiohene) (P3HT)/asphaltene blends as potential materials for the design of [...] Read more.

Further development and commercialization of bulk heterojunction (BHJ) solar cells require the search for novel low-cost materials. The present study addresses the relations between the asphaltenes’ chemical structure and the morphology of the poly(3-hexylthiohene) (P3HT)/asphaltene blends as potential materials for the design of BHJ solar cells. By means of all-atom molecular dynamics simulations, the formation of heterophase morphology is observed for the P3HT-based blends with carboxyl-containing asphaltenes, as well as the aggregation of the asphaltenes into highly ordered stacks. Although the π–π interactions between the polyaromatic cores of the asphaltenes in solutions are sufficient for the molecules to aggregate into ordered stacks, in a blend with a conjugated polymer, additional stabilizing factors are required, such as hydrogen bonding between carboxyl groups. It is found that the asphaltenes’ aliphatic side groups may improve significantly the miscibility between the polymer and the asphaltenes, thereby preventing the formation of heterophase morphology. The results also demonstrate that the carboxyl-containing asphaltenes/P3HT ratio should be at least 1:1, as a decrease in concentration of the asphaltenes leads to the folding of the polymer chains, lower ordering in the polymer phase and the destruction of the interpenetrating 3D structure formed by P3HT and the asphaltene phases. Overall, the results of the present study for the first time reveal the aggregation behavior of the asphaltenes of varying chemical structures in P3HT, as well the influence of their presence and concentration on the polymer phase structure and blend morphology, paving the way for future development of BHJ solar cells based on the conjugated polymer/asphaltene blends. Full article

(This article belongs to the Special Issue Nanomaterials Investigation by Molecular Dynamics Simulation)

► Show Figures

Figure 1

17 pages, 4445 KiB

Open AccessArticle

Determination of Pb²⁺ by Colorimetric Method Based on Catalytic Amplification of Ag Nanoparticles Supported by Covalent Organic Frameworks

by Dongmei Yao, Huiling Bi, Huimin Gong, Hongfang Lai and Sufen Lu

Nanomaterials 2022, 12(16), 2866; https://doi.org/10.3390/nano12162866 - 19 Aug 2022

Cited by 6 | Viewed by 2192

Abstract

In this paper, covalent organic frameworks (COFs) are prepared by solvothermal synthesis using 1,3,5-benzenetricarboxaldehyde and benzidine as ligands. Then, using COFs as a template, AgCOFs with high catalytic activity is prepared by in situ loading silver nanoparticles (AgNC) on the surface of COFs [...] Read more.

In this paper, covalent organic frameworks (COFs) are prepared by solvothermal synthesis using 1,3,5-benzenetricarboxaldehyde and benzidine as ligands. Then, using COFs as a template, AgCOFs with high catalytic activity is prepared by in situ loading silver nanoparticles (AgNC) on the surface of COFs by sodium borohydride reduction method. AgCOFs are characterized by TEM, SEM, FTIR and XRD. At the same time, the catalytic ability of AgCOFs for trisodium citrate-AgNO₃ nanosilver reaction is studied. The results show that AgCOFs can catalyze the reaction of trisodium citrate-AgNO₃ to generate silver nanoparticles (AgNPs). The solution color of the system gradually changes from colorless to yellow, and the absorbance value increases. Based on the catalytic reaction of AgCOFs and the regulation effect of nucleic acid aptamer reaction on AgCOFs, a new “on–off–on” colorimetric analysis platform is constructed and applied to the detection of trace Pb²⁺ in water samples. This analytical platform is simple, sensitive and selective. Finally, the catalytic mechanism of the system is discussed to verify the feasibility of constructing a colorimetric analysis platform. Full article

► Show Figures

Figure 1

2 pages, 180 KiB

Open AccessEditorial

Non-Cytotoxic Nanoparticles

by Raphaël Schneider

Nanomaterials 2022, 12(16), 2865; https://doi.org/10.3390/nano12162865 - 19 Aug 2022

Viewed by 1165

Abstract

For several decades, nanoparticles (NPs) are becoming widely used in various industries, in electronics, agriculture, textile production or medicine [...] Full article

(This article belongs to the Special Issue Non-cytotoxic Nanoparticles)

9 pages, 5269 KiB

Open AccessArticle

A Novel and Cost-Effective CsVO₃ Quantum Dots for Optoelectronic and Display Applications

by Ganji Seeta Rama Raju, Ganji Lakshmi Varaprasad, Jeong-Hwan Lee, Jin Young Park, Nilesh R. Chodankar, Kugalur Shanmugam Ranjith, Eluri Pavitra, Yun Suk Huh and Young-Kyu Han

Nanomaterials 2022, 12(16), 2864; https://doi.org/10.3390/nano12162864 - 19 Aug 2022

Cited by 1 | Viewed by 2291

Abstract

Quantum dots (QDs) have an unparalleled ability to mimic true colors due to their size-tunable optical and electronic properties, which make them the most promising nanoparticles in various fields. Currently, the majority of QDs available in the market are cadmium, indium, and lead-based [...] Read more.

Quantum dots (QDs) have an unparalleled ability to mimic true colors due to their size-tunable optical and electronic properties, which make them the most promising nanoparticles in various fields. Currently, the majority of QDs available in the market are cadmium, indium, and lead-based materials but the toxicity and unstable nature of these QDs restricts their industrial and practical applications. To avoid using heavy metal ions, especially cadmium, the current research is focused on the fabrication of perovskite and vanadate QDs. Herein, we report the facile synthesis of a novel and cost-effective CsVO₃ QDs for the first time. The sizes of the CsVO₃ QDs produced were tuned from 2 to 10 nm by varying the reaction temperature from 140 to 190 °C. On increasing QD size, a continuous red shift was observed in absorption and emission spectra, signifying the presence of quantum confinement. In addition, along with CsVO₃ QDs, the CsVO₃ nanosheets self-assembled microflower-like particles were found as residue after the centrifugation; the X-ray diffraction indicated an orthorhombic structure. Under 365 nm excitation, these CsVO₃ microflower-like particles exhibited broad emission with CIE coordinates in the white emission region. The acquired results suggest that CsVO₃ QDs may represent a new class of cadmium-free materials for optoelectronic and biomedical applications. Full article

(This article belongs to the Special Issue Nanophosphors for Solid-State Lighting and Biomedical Applications)

► Show Figures

Figure 1

9 pages, 2073 KiB

Open AccessArticle

Efficient Reduction Photocatalyst of 4-Nitrophenol Based on Ag-Nanoparticles-Doped Porous ZnO Heterostructure

by Shali Lin, Xiaohu Mi, Lei Xi, Jinping Li, Lei Yan, Zhengkun Fu and Hairong Zheng

Nanomaterials 2022, 12(16), 2863; https://doi.org/10.3390/nano12162863 - 19 Aug 2022

Cited by 6 | Viewed by 2419

Abstract

Oxide-supported Ag nanoparticles have been widely reported as a good approach to improve the stability and reduce the cost of photocatalysts. In this work, a Ag-nanoparticles-doped porous ZnO photocatalyst was prepared by using metal–organic frameworks as a sacrificial precursor and the catalytic activity [...] Read more.

Oxide-supported Ag nanoparticles have been widely reported as a good approach to improve the stability and reduce the cost of photocatalysts. In this work, a Ag-nanoparticles-doped porous ZnO photocatalyst was prepared by using metal–organic frameworks as a sacrificial precursor and the catalytic activity over 4-nitrophenol was determined. The Ag-nanoparticles-doped porous ZnO heterostructure was evaluated by UV, XRD, and FETEM, and the catalytic rate constant was calculated by the change in absorbance value at 400 nm of 4-nitrophenol. The photocatalyst with a heterogeneous structure is visible, light-responsive, and beneficial to accelerating the catalytic rate. Under visible light irradiation, the heterostructure showed excellent catalytic activity over 4-nitrophenol due to the hot electrons induced by the localized surface plasmon resonance of Ag nanoparticles. Additionally, the catalytic rates of 4 nm/30 nm Ag nanoparticles and porous/nonporous ZnO were compared. We found that the as-prepared Ag-nanoparticles-doped porous ZnO heterostructure catalyst showed enhanced catalytic performance due to the synergetic effect of Ag nanoparticles and porous ZnO. This study provides a novel heterostructure photocatalyst with potential applications in solar energy and pollutant disposal. Full article

(This article belongs to the Special Issue Plasmon Assisted Near-Field Manipulation and Photocatalysis)

► Show Figures

Figure 1

13 pages, 3382 KiB

Open AccessArticle

3D Printing of Ultrathin MXene toward Tough and Thermally Resistant Nanocomposites

by Yuewei Li, Ranjith Kumar Kankala, Ai-Zheng Chen and Shi-Bin Wang

Nanomaterials 2022, 12(16), 2862; https://doi.org/10.3390/nano12162862 - 19 Aug 2022

Cited by 3 | Viewed by 2201

Abstract

Liquid crystal display (LCD)-based 3D printing, a facile and cost-effective manufacturing technique, is often applied when fabricating objects with porcelain structures using photosensitive resins (PSRs). Currently, 3D printed constructions are typically used as models for demonstration purposes rather than industrial applications because of [...] Read more.

Liquid crystal display (LCD)-based 3D printing, a facile and cost-effective manufacturing technique, is often applied when fabricating objects with porcelain structures using photosensitive resins (PSRs). Currently, 3D printed constructions are typically used as models for demonstration purposes rather than industrial applications because of their poor performance. In this study, we prepared nanocomposites by incorporating Ti₃C₂ MXene nanosheets to enhance the overall characteristics of a PSR, including mechanical properties and thermal resistance. Notably, the designed nanocomposites showed optimum performance at an MXene loading of 0.5% w/w. The mechanical properties of the designed nanocomposites confirmed the enhanced ultimate tensile and flexural strengths (by 32.1% and 42.7%, respectively), at 0.5% w/w MXene loading. Moreover, the incorporated MXene presented no substantial influence on the toughness of the PSR. The glass transition and thermal degradation temperatures at 5% weight loss increased by 7.4 and 10.6 °C, respectively, resulting predominantly from the hydrogen bonding between the PSR and MXene. Together, the experimental results indicate that the designed PSR/MXene nanocomposites are expected to replace pristine resins for LCD printing in various practical applications. Full article

(This article belongs to the Special Issue Preparation and Characterization of Nanomaterials with Multifunctional Properties)

► Show Figures

Figure 1

13 pages, 8464 KiB

Open AccessEditor’s ChoiceArticle

RPA Plasmons in Graphene Nanoribbons: Influence of a VO₂ Substrate

by Mousa Bahrami and Panagiotis Vasilopoulos

Nanomaterials 2022, 12(16), 2861; https://doi.org/10.3390/nano12162861 - 19 Aug 2022

Cited by 1 | Viewed by 2129

Abstract

We study the effect of the phase-change material VO

_{2}

on plasmons in metallic arm-chair graphene nanoribbons (AGNRs) within the random-phase approximation (RPA) for intra- and inter-band transitions. We assess the influence of temperature as a knob for the transition from the insulating [...] Read more.

We study the effect of the phase-change material VO

_{2}

on plasmons in metallic arm-chair graphene nanoribbons (AGNRs) within the random-phase approximation (RPA) for intra- and inter-band transitions. We assess the influence of temperature as a knob for the transition from the insulating to the metallic phase of VO

_{2}

on localized and propagating plasmon modes. We show that AGNRs support localized and propagating plasmon modes and contrast them in the presence and absence of VO

_{2}

for intra-band (SB) transitions while neglecting the influence of a substrate-induced band gap. The presence of this gap results in propagating plasmon modes in two-band (TB) transitions. In addition, there is a critical band gap below and above which propagating modes have a linear negative or positive velocity. Increasing the band gap shifts the propagating and localized modes to higher frequencies. In addition, we show how the normalized Fermi velocity increases plasmon modes frequency. Full article

(This article belongs to the Special Issue Photoemission and Excitation Properties of Nanomaterials by Computational Methods)

► Show Figures

Figure 1

16 pages, 3542 KiB

Open AccessArticle

Thermally Stable Magneto-Plasmonic Nanoparticles for SERS with Tunable Plasmon Resonance

by Lina Mikoliunaite, Martynas Talaikis, Aleksandra Michalowska, Jorunas Dobilas, Voitech Stankevic, Andrzej Kudelski and Gediminas Niaura

Nanomaterials 2022, 12(16), 2860; https://doi.org/10.3390/nano12162860 - 19 Aug 2022

Cited by 16 | Viewed by 2639

Abstract

Bifunctional magneto-plasmonic nanoparticles that exhibit synergistically magnetic and plasmonic properties are advanced substrates for surface-enhanced Raman spectroscopy (SERS) because of their excellent controllability and improved detection potentiality. In this study, composite magneto-plasmonic nanoparticles (Fe₃O₄@AgNPs) were formed by mixing colloid [...] Read more.

Bifunctional magneto-plasmonic nanoparticles that exhibit synergistically magnetic and plasmonic properties are advanced substrates for surface-enhanced Raman spectroscopy (SERS) because of their excellent controllability and improved detection potentiality. In this study, composite magneto-plasmonic nanoparticles (Fe₃O₄@AgNPs) were formed by mixing colloid solutions of 50 nm-sized magnetite nanoparticles with 13 nm-sized silver nanoparticles. After drying of the layer of composite Fe₃O₄@AgNPs under a strong magnetic field, they outperformed the conventional silver nanoparticles during SERS measurements in terms of signal intensity, spot-to-spot, and sample-to-sample reproducibility. The SERS enhancement factor of Fe₃O₄@AgNP-adsorbed 4-mercaptobenzoic acid (4-MBA) was estimated to be 3.1 × 10⁷ for a 633 nm excitation. In addition, we show that simply by changing the initial volumes of the colloid solutions, it is possible to control the average density of the silver nanoparticles, which are attached to a single magnetite nanoparticle. UV-Vis and SERS data revealed a possibility to tune the plasmonic resonance frequency of Fe₃O₄@AgNPs. In this research, the plasmon resonance maximum varied from 470 to 800 nm, suggesting the possibility to choose the most suitable nanoparticle composition for the particular SERS experiment design. We emphasize the increased thermal stability of composite nanoparticles under 532 and 442 nm laser light irradiation compared to that of bare Fe₃O₄ nanoparticles. The Fe₃O₄@AgNPs were further characterized by XRD, TEM, and magnetization measurements. Full article

(This article belongs to the Special Issue SERS/SERRS-Active Nanostructures and Nanocomposites)

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Nanomaterials, Volume 12, Issue 16 (August-2 2022) – 159 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI