Nanomaterials

21 pages, 13832 KiB

Open AccessReview

On-Surface Ullmann-Type Coupling Reactions of Aryl Halide Precursors with Multiple Substituted Sites

by Qiwei Liu, Yuhong Gao and Chi Zhang

Nanomaterials 2025, 15(9), 646; https://doi.org/10.3390/nano15090646 - 24 Apr 2025

The fabrication of low-dimensional nanostructures through on-surface synthesis has emerged as a promising strategy for developing high-precision electronic devices. Among various reactions, Ullmann-type coupling (with carbon–halogen bond activation) stands out in this field as a prevalent methodology due to its straightforward activation process, [...] Read more.

The fabrication of low-dimensional nanostructures through on-surface synthesis has emerged as a promising strategy for developing high-precision electronic devices. Among various reactions, Ullmann-type coupling (with carbon–halogen bond activation) stands out in this field as a prevalent methodology due to its straightforward activation process, highly programmable characteristics, and remarkable synthetic efficiency. To date, on-surface Ullmann-type coupling reactions of aryl halide precursors have been extensively studied with the assistance of in situ characterization techniques. The resulting carbon-based nanostructures exhibit high structural diversity and significant potential for applications in molecular electronics. This review categorizes recent progress in the precise preparation of carbon-based nanostructures based on molecular precursors with distinct halogen substituted sites, including para-, meta-, and ortho-sites, peri- and bay-regions, and their combination. In addition, systematic analysis and comparative discussion of their respective characteristics is also provided. Full article

(This article belongs to the Special Issue Functionalized Nanostructures on Surfaces and at Interfaces)

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15 pages, 1093 KiB

Open AccessArticle

Ellipsometric Surface Oxidation Model of ALD-Grown Vanadium Oxide Mixed-Valence System

by Xiaojie Sun, Shuguang Wang, Qingyuan Cai, Jingze Liu, Changhai Li, Ertao Hu, Jing Li, Songyou Wang, Yuxiang Zheng, Liangyao Chen and Youngpak Lee

Nanomaterials 2025, 15(9), 645; https://doi.org/10.3390/nano15090645 - 24 Apr 2025

Abstract

Vanadium and oxygen form a complex system of vanadium oxides with multiple phases and mixed valency, increasing the difficulty of characterization. In this work, amorphous vanadium oxide thin films with mixed valence states were fabricated by atomic layer deposition, and then post-annealing was [...] Read more.

Vanadium and oxygen form a complex system of vanadium oxides with multiple phases and mixed valency, increasing the difficulty of characterization. In this work, amorphous vanadium oxide thin films with mixed valence states were fabricated by atomic layer deposition, and then post-annealing was conducted for crystalline films. For the surface analysis of this mixed-valence system, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) were employed. However, XPS is only able to quasi-quantitatively determine the surface-proximity oxidation states. To account for the inadequacy of surface-sensitive XPS and AES techniques, a surface oxidation model (SOM) was proposed for the ellipsometric modeling of the mixed-valence system. Furthermore, by conducting air thermal oxidation (ATO) experiments, the four sets of fitting parameters of SOM were decreased to three, lowering the system complexity. This study is expected to help with the analysis of vanadium oxide mixed-valence systems and other multivalent metal oxide systems. Full article

(This article belongs to the Special Issue Nano-Photonics: Subwavelength Optical Elements, Metasurfaces, Plasmonics and Quantum Photonics: 2nd Edition)

16 pages, 4215 KiB

Open AccessReview

Progress in UV Photodetectors Based on ZnO Nanomaterials: A Review of the Detection Mechanisms and Their Improvement

by Gaoda Li, Bolang Cheng, Haibo Zhang, Xinghua Zhu and Dingyu Yang

Nanomaterials 2025, 15(9), 644; https://doi.org/10.3390/nano15090644 - 24 Apr 2025

Abstract

Recent advancements in ultraviolet (UV) photodetection technology have driven intensive research on zinc oxide (ZnO) nanomaterials due to their exceptional optoelectronic properties. This review systematically examines the fundamental detection mechanisms in ZnO-based UV photodetectors (UVPDs), including photoconductivity effects, the threshold dimension phenomenon and [...] Read more.

Recent advancements in ultraviolet (UV) photodetection technology have driven intensive research on zinc oxide (ZnO) nanomaterials due to their exceptional optoelectronic properties. This review systematically examines the fundamental detection mechanisms in ZnO-based UV photodetectors (UVPDs), including photoconductivity effects, the threshold dimension phenomenon and light-modulated interface barriers. Based on these mechanisms, a large surface barrier due to surface-adsorbed O₂ is generally constructed to achieve a high sensitivity. However, this improvement is obtained with a decrease in response speed due to the slow desorption and re-adsorption processes of surface O₂ during UV light detection. Various improvement strategies have been proposed to overcome this drawback and keep the high sensitivity, including ZnO–organic semiconductor interfacing, defect engineering and doping, surface modification, heterojunction and the Schottky barrier. The general idea is to modify the adsorption state of O₂ or replace the adsorbed O₂ with another material to build a light-regulated surface or an interface barrier, as surveyed in the third section. The critical trade-off between sensitivity and response speed is also addressed. Finally, after a summary of these mechanisms and the improvement methods, this review is concluded with an outlook on the future development of ZnO nanomaterial UVPDs. Full article

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

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14 pages, 3546 KiB

Open AccessArticle

Mechanically Exfoliated Multilayer Graphene-Supported Ni-MOF Parallelogram Nanosheets for Enhanced Supercapacitor Performance

by Zhiheng Li, Junming Xu, Xinqi Ding, Haoran Zhu and Jianfeng Wu

Nanomaterials 2025, 15(9), 643; https://doi.org/10.3390/nano15090643 - 23 Apr 2025

Abstract

Metal–organic frameworks (MOFs) are regarded as advanced supercapacitor materials owing to their high surface area, redox-active sites, and porosity. However, their insufficient charge carrier mobility remains a critical limitation for practical application. Integrating MOFs with conductive carbon substrates is an effective strategy to [...] Read more.

Metal–organic frameworks (MOFs) are regarded as advanced supercapacitor materials owing to their high surface area, redox-active sites, and porosity. However, their insufficient charge carrier mobility remains a critical limitation for practical application. Integrating MOFs with conductive carbon substrates is an effective strategy to break through this limitation. However, conventional carbon materials often require complex preparation methods and pre-activation steps for use in MOF composites. Herein, multilayer graphene (MLG) mechanically exfoliated from expandable graphite is employed as a substrate, and a van der Waals force-assisted chemical deposition method is developed to directly anchor Ni-MOF onto its surface without requiring pre-activation treatment. To optimize the composite, Ni-MOFs with various mass loadings are synthesized on MLG surface. The morphological characteristics and energy storage performance of these composites are thoroughly characterized. Ni-MOF/MLG-0.30 (with a 70.8% Ni-MOF loading on MLG) features a porous stacking structure of well-crystalline Ni-MOF parallelogram nanosheets on MLG, exhibiting optimal electrochemical performance. The composite achieves 1071.4 F g⁻¹ at 1 A g⁻¹, and a capacitance retention of 64.9% at the elevated current density of 10 A g⁻¹. Meanwhile, the composite maintains 63.2% of its initial capacitance after 5000 charge/discharge cycles at 4 A g⁻¹. A hybrid supercapacitor is fabricated using Ni-MOF/MLG-0.30 cathode and activated carbon anode, delivering 27.9 Wh kg⁻¹ energy density at 102.5 W kg⁻¹ power output. Full article

(This article belongs to the Special Issue The Application of Nanoscale Materials in Batteries, Sensors and Supercapacitors (2nd Edition))

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16 pages, 2112 KiB

Open AccessArticle

Tunable Magnetic Heating in La_0.51Sr_0.49MnO₃ and La_0.51Dy_0.045Sr_0.445MnO₃ Nanoparticles: Frequency- and Amplitude-Dependent Behavior

by Mourad Smari, Monica Viorica Moisiuc, Mohammad Y. Al-Haik, Iordana Astefanoaei, Alexandru Stancu, Fedor Shelkovyi, Radel Gimaev, Julia Piashova, Vladimir Zverev and Yousef Haik

Nanomaterials 2025, 15(9), 642; https://doi.org/10.3390/nano15090642 - 23 Apr 2025

Abstract

The use of perovskite manganite nanoparticles in magnetic hyperthermia has attracted significant attention due to their tunable magnetic properties and high specific absorption rate (SAR). In this work, we present a combined experimental and theoretical investigation of the frequency- and amplitude-dependent magnetic heating [...] Read more.

The use of perovskite manganite nanoparticles in magnetic hyperthermia has attracted significant attention due to their tunable magnetic properties and high specific absorption rate (SAR). In this work, we present a combined experimental and theoretical investigation of the frequency- and amplitude-dependent magnetic heating behavior of La_0.51Sr_0.49MnO₃ (LSMO) and Dy-doped La_0.51Dy_0.045Sr_0.445MnO₃ (DLSMO) nanoparticles. The nanoparticles were synthesized via the sol–gel method and characterized by XRD and SEM, while SAR values were experimentally evaluated under varying magnetic field strengths (60–120 Oe) and frequencies (150–300 kHz). In parallel, theoretical modeling based on Néel and Brownian relaxation mechanisms was employed to predict SAR behavior as a function of particle size, magnetic anisotropy, and fluid viscosity. The results reveal that Dy doping enhances magnetic anisotropy, which modifies the relaxation dynamics and leads to a reduction in SAR. The model identifies the optimal nanoparticle size (~18–20 nm) and ferrofluid viscosity to maximize heating efficiency. This combined approach provides a comprehensive framework for designing and optimizing perovskite-based nanoparticles for magnetic hyperthermia applications. Full article

(This article belongs to the Section Physical Chemistry at Nanoscale)

10 pages, 2744 KiB

Open AccessArticle

Facile Synthesis of Polypyrrole/MnO₂/Carbon Cloth Composites for Supercapacitor Electrodes

by Yan Chen, Hanyue He, Min Liu, He Xu, Haibo Zhang, Xinghua Zhu and Dingyu Yang

Nanomaterials 2025, 15(9), 641; https://doi.org/10.3390/nano15090641 - 23 Apr 2025

Abstract

In the development of flexible smart electronics, fabricating electrodes with optimized architectures to achieve superior electrochemical performance remains a significant challenge. This study presents a two-step synthesis and characterization of a polypyrrole (PPy)-MnO₂/carbon cloth (CC) nanocomposite. The MnO₂/CC substrate [...] Read more.

In the development of flexible smart electronics, fabricating electrodes with optimized architectures to achieve superior electrochemical performance remains a significant challenge. This study presents a two-step synthesis and characterization of a polypyrrole (PPy)-MnO₂/carbon cloth (CC) nanocomposite. The MnO₂/CC substrate was first prepared via the hydrothermal method, followed by uniform PPy coating through vapor-phase polymerization in the presence of an oxidizing agent. Electrochemical measurements revealed substantial enhancement in performance, with the specific capacitance increasing from 123.1 mF/cm² for the MnO₂/CC composite to 324.5 mF/cm² for the PPy/MnO₂/CC composite at a current density of 2.5 mA/cm². This remarkable improvement can be attributed to the synergistic effects between the conductive PPy polymer and MnO₂/CC substrate and the formation of additional ion transport channels facilitated by the PPy coating. This work provides valuable insights for designing high-performance electrode materials and advances the development of composite-based energy storage devices. Full article

(This article belongs to the Special Issue Application of Biomass-Derived Nanomaterials in Batteries and Supercapacitors)

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15 pages, 4751 KiB

Open AccessArticle

SnO Nanosheet Transistor with Remarkably High Hole Effective Mobility and More than Six Orders of Magnitude On-Current/Off-Current

by Kuan-Chieh Chen, Jiancheng Wu, Pheiroijam Pooja and Albert Chin

Nanomaterials 2025, 15(9), 640; https://doi.org/10.3390/nano15090640 - 23 Apr 2025

Abstract

Using novel SiO₂ surface passivation and ultraviolet (UV) light anneal, a 12 nm thick SnO p-type FET (pFET) shows hole effective mobilities (µ_eff) of more than 100 cm²/V·s and 31.1 cm²/V·s at hole densities (Q_h [...] Read more.

Using novel SiO₂ surface passivation and ultraviolet (UV) light anneal, a 12 nm thick SnO p-type FET (pFET) shows hole effective mobilities (µ_eff) of more than 100 cm²/V·s and 31.1 cm²/V·s at hole densities (Q_h) of 1 × 10¹¹ and 5 × 10¹² cm⁻², respectively. To further improve the on-current/off-current (I_ON/I_OFF), an ultra-thin 7 nm thick SnO nanosheet pFET shows a record-breaking I_ON/I_OFF of 6.9 × 10⁶ and remarkable µ_eff values of ~70 cm²/V·s and 20.7 cm²/V·s at Q_h of 1 × 10¹¹ cm⁻² and 5 × 10¹² cm⁻², respectively. This is the first report of an oxide semiconductor transistor achieving a hole effective mobility µ_eff that reaches 20% of that in single-crystal Si pFETs at an ultra-thin body thickness of 7 nm. In sharp contrast, the control SnO nanosheet pFET without surface passivation or UV anneal exhibits a small I_ON/I_OFF of 1.8 × 10⁴ and a µ_eff of only 6.1 cm²/V·s at 5 × 10¹² cm⁻² Q_h. The enhanced SnO pFET performance is attributed to reduced defects and improved quality in the SnO channel, as confirmed by decreased charges related to sub-threshold swing (SS) and threshold voltage (Vth) shift. Such a large improvement is further supported by the increased Sn²⁺ after passivation and UV anneal, as evidenced by X-ray photoelectron spectroscopy (XPS) analysis. The I_ON/I_OFF ratio exceeding six orders of magnitude, remarkably high hole µ_eff, and excellent two-month stability demonstrate that this pFET is a strong candidate for integration with SnON nFETs in next-generation ultra-high-definition displays and monolithic three-dimensional integrated circuits (3D ICs). Full article

(This article belongs to the Special Issue Integrated Circuit Research for Nanoscale Field-Effect Transistors)

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16 pages, 9146 KiB

Open AccessArticle

Aging Characteristics of ZSM-5 Zeolite on Low-Frequency Acoustic Applications

by Mingbo Guo, Yijun Wang, Lei Zhang, Junran Lu, Chang Gong, Wanning Zhang, Yuxi Fang, Xinyuan Zhu and Shunai Che

Nanomaterials 2025, 15(9), 639; https://doi.org/10.3390/nano15090639 - 23 Apr 2025

Abstract

Zeolite is increasingly recognized for its enhancement of low-frequency acoustic performance in microspeakers. The aging characteristics of zeolite have been regarded as the critical factor for the commercial viability of mobile phones products, but the mechanism remains ambiguous. Here, the low-frequency acoustic performance [...] Read more.

Zeolite is increasingly recognized for its enhancement of low-frequency acoustic performance in microspeakers. The aging characteristics of zeolite have been regarded as the critical factor for the commercial viability of mobile phones products, but the mechanism remains ambiguous. Here, the low-frequency acoustic performance of hierarchically structured ZSM-5 was investigated through aging with water and acetic acid (AA). It was discovered that water vapor augmented the resonance offset as it enhanced the structure of the zeolite, resulting in a lower water content. The resonance offset of ZSM-5 significantly decreased after the adsorption of AA vapor, as excessive AA was adsorbed through both physical and chemical adsorption, causing partial destruction of supermicropore and mesopores. The performance of ZMS-5 stored with vapor of AA and water mixture did not significantly deteriorate, indicating that water effectively protected the pores of zeolite to prevent excessive adsorption of AA. This was attributed to the fact that water was adsorbed by Brønsted acid sites of ZSM-5 more preferentially than AA, thereby avoiding excessive adsorption of AA. Full article

(This article belongs to the Section Physical Chemistry at Nanoscale)

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21 pages, 19032 KiB

Open AccessArticle

Synthesis of Copper Nanowires Using Monoethanolamine and the Application in Transparent Conductive Films

by Xiangyun Zha, Depeng Gong, Wanyu Chen, Lili Wu and Chaocan Zhang

Nanomaterials 2025, 15(9), 638; https://doi.org/10.3390/nano15090638 - 22 Apr 2025

Abstract

Copper nanowires (Cu NWs) are considered a promising alternative to indium tin oxide (ITO) and silver nanowires (Ag NWs) due to their excellent electrical conductivity, mechanical properties, abundant reserves, and low cost. They have been widely applied in various optoelectronic devices. In this [...] Read more.

Copper nanowires (Cu NWs) are considered a promising alternative to indium tin oxide (ITO) and silver nanowires (Ag NWs) due to their excellent electrical conductivity, mechanical properties, abundant reserves, and low cost. They have been widely applied in various optoelectronic devices. In this study, Cu NWs were synthesized using copper chloride (CuCl₂) as the precursor, monoethanolamine (MEA) as the complexing agent, and hydrated hydrazine (N₂H₄) as the reducing agent under strongly alkaline conditions at 60 °C. Notably, this is the first time that MEA has been employed as a complexing agent in this synthesis method for Cu NWs. Through a series of experiments, the optimal conditions for the CuCl₂–MEA–N₂H₄ system in Cu NWs synthesis were determined. This study revealed that the presence of amines plays a crucial role in nanowire formation, as the co-ordination of MEA with copper in this system provides selectivity for the nanowire growth direction. MEA prevents the excessive conversion of Cu(I) complexes into Cu₂O octahedral precipitates and exhibits an adsorption effect during Cu NWs formation. The different adsorption tendencies of MEA at the nanowire ends and lateral surfaces, depending on its concentration, influence the growth of the Cu NWs, as directly reflected by changes in their diameter and length. At an MEA concentration of 210 mM, the synthesized Cu NWs have an average diameter of approximately 101 nm and a length of about 28 μm. To fabricate transparent conductive films, the Cu NW network was transferred onto a polyethylene terephthalate (PET) substrate by applying a pressure of 20 MPa using a tablet press to ensure strong adhesion between the Cu NW-coated mixed cellulose ester (MCE) filter membrane and the PET substrate. Subsequently, the MCE membrane was dissolved by acetone and isopropanol immersion. The resulting Cu NW transparent conductive film exhibited a sheet resistance of 52 Ω sq⁻¹ with an optical transmittance of 86.7%. Full article

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

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26 pages, 26551 KiB

Open AccessArticle

Antimicrobial Coatings Based on Hybrid Iron Oxide Nanoparticles

by Doina-Antonia Mercan, Dana-Ionela Tudorache (Trifa), Adelina-Gabriela Niculescu, Laurenţiu Mogoantă, George Dan Mogoşanu, Alexandra Cătălina Bîrcă, Bogdan Ștefan Vasile, Ariana Hudiță, Ionela Cristina Voinea, Miruna S. Stan, Tony Hadibarata, Dan Eduard Mihaiescu, Alexandru Mihai Grumezescu and Adina Alberts

Nanomaterials 2025, 15(9), 637; https://doi.org/10.3390/nano15090637 - 22 Apr 2025

Abstract

This study presents the preparation of hybrid iron oxide nanocomposites through a two-step process combining microfluidic-assisted synthesis and post-synthetic surface modification. Fe₃O₄ nanoparticles were synthesized and simultaneously functionalized with salicylic acid using a three-dimensional vortex-type microfluidic chip, enabling rapid and [...] Read more.

This study presents the preparation of hybrid iron oxide nanocomposites through a two-step process combining microfluidic-assisted synthesis and post-synthetic surface modification. Fe₃O₄ nanoparticles were synthesized and simultaneously functionalized with salicylic acid using a three-dimensional vortex-type microfluidic chip, enabling rapid and uniform particle formation. The resulting Fe₃O₄/SA nanostructures were further modified with either silver or copper oxide to form iron oxide nanocomposites with enhanced antimicrobial functionality. These nanocomposites were subsequently integrated into silica aerogel matrices using a dip-coating approach to improve surface dispersion, structural stability, and biocompatibility. The structural and morphological properties of the samples were investigated using XRD, FT-IR, TEM with SAED analysis, and Raman microscopy. In vitro cytotoxicity and antimicrobial assays demonstrated that Fe₃O₄/SA–Ag and Fe₃O₄/SA–CuO exhibit potent antibacterial activity and cell type-dependent biocompatibility. In vivo biodistribution studies showed no accumulation in major organs and selective clearance via the spleen, validating the systemic safety of the platform. These findings highlight the potential of the synthesized nanocomposites as biocompatible, antimicrobial coatings for advanced biomedical surfaces. Full article

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

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15 pages, 5562 KiB

Open AccessReview

Avalanche Multiplication in Two-Dimensional Layered Materials: Principles and Applications

by Zhangxinyu Zhou, Mengyang Kang, Yueyue Fang, Piotr Martyniuk and Hailu Wang

Nanomaterials 2025, 15(9), 636; https://doi.org/10.3390/nano15090636 - 22 Apr 2025

Abstract

The avalanche multiplication effect, capable of significantly amplifying weak optical or electrical signals, plays a pivotal role in enhancing the performance of electronic and optoelectronic devices. This effect has been widely employed in devices such as avalanche photodiodes, impact ionization avalanche transit time [...] Read more.

The avalanche multiplication effect, capable of significantly amplifying weak optical or electrical signals, plays a pivotal role in enhancing the performance of electronic and optoelectronic devices. This effect has been widely employed in devices such as avalanche photodiodes, impact ionization avalanche transit time diode, and impact ionization field-effect transistors, enabling diverse applications in biomedical imaging, 3D LIDAR, high-frequency microwave circuits, and optical fiber communications. However, the evolving demands in these fields require avalanche devices with superior performance, including lower power consumption, reduced avalanche threshold energy, higher efficiency, and improved sensitivity. Over the years, significant efforts have been directed towards exploring novel device architectures and multiplication mechanisms. The emergence of two-dimensional (2D) materials, characterized by their exceptional light-matter interaction, tunable bandgaps, and ease of forming junctions, has opened up new avenues for developing high-performance avalanche devices. This review provides an overview of carrier multiplication mechanisms and key performance metrics for avalanche devices. We discuss several device structures leveraging the avalanche multiplication effect, along with their electrical and optoelectronic properties. Furthermore, we highlight representative applications of avalanche devices in logic circuits, optoelectronic components, and neuromorphic computing systems. By synthesizing the principles and applications of the avalanche multiplication effect, this review aims to offer insightful perspectives on future research directions for 2D material-based avalanche devices. Full article

(This article belongs to the Special Issue Photonics/Optoelectronics Properties and Applications of Two-Dimensional Heterostructures)

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16 pages, 2854 KiB

Open AccessArticle

Optimal Selection and Experimental Verification of Wide-Bandgap Semiconductor for Betavoltaic Battery

by Jiachen Zhang, Kunlun Lv, Yuan Yin, Yuqian Gao, Ye Tian, Yuncheng Han and Jun Tang

Nanomaterials 2025, 15(9), 635; https://doi.org/10.3390/nano15090635 - 22 Apr 2025

Abstract

Wide-bandgap semiconductor betavoltaic batteries have a promising prospect in Micro-Electro-Mechanical Systems for high power density and long working life, but their material selection is still controversial. Specifically, the silicon carbide (SiC) betavoltaic battery was reported to have higher efficiency, although its bandgap is [...] Read more.

Wide-bandgap semiconductor betavoltaic batteries have a promising prospect in Micro-Electro-Mechanical Systems for high power density and long working life, but their material selection is still controversial. Specifically, the silicon carbide (SiC) betavoltaic battery was reported to have higher efficiency, although its bandgap is lower than that of gallium nitride (GaN) or diamond, which is inconsistent with general assumptions. In this work, the effects of different semiconductor characteristics on the battery energy conversion process are systematically analyzed to explain this phenomenon, including beta particle energy deposition, electron–hole pair (EHP) creation energy and EHPs collection efficiency. Device efficiencies of the betavoltaic battery using SiC, GaN, diamond, gallium oxide (Ga₂O₃), aluminum nitride (AlN) and boron nitride (BN) are compared to determine the optimum semiconductor. Results show that SiC for the betavoltaic battery has higher efficiency than GaN, Ga₂O₃ and AlN because of higher EHPs collection efficiency, less energy loss and fewer material defects, which is the optimal selection currently. SiC betavoltaic batteries were prepared, with the device efficiency having reached 14.88% under an electron beam, and the device efficiency recorded as 7.31% under an isotope source, which are consistent with the predicted results. This work provides a theoretical and experimental foundation for the material selection of betavoltaic batteries. Full article

(This article belongs to the Section Theory and Simulation of Nanostructures)

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10 pages, 1634 KiB

Open AccessReview

Electrocatalytic Innovations at Atomic Scale: From Single-Atom to Periodic Ensembles for Sustainable Energy Conversion

by Longlu Wang and Yang Liu

Nanomaterials 2025, 15(8), 634; https://doi.org/10.3390/nano15080634 - 21 Apr 2025

Abstract

Atomically dispersed catalysts, including single-atom, dual-atom, and periodic single-metal site catalysts, have revolutionized electrocatalysis by merging atomic precision with heterogeneous stability. This review traces their evolution from pioneering stabilization strategies to advanced microenvironment engineering, enabling breakthroughs in oxygen reduction, hydrogen evolution, and CO [...] Read more.

Atomically dispersed catalysts, including single-atom, dual-atom, and periodic single-metal site catalysts, have revolutionized electrocatalysis by merging atomic precision with heterogeneous stability. This review traces their evolution from pioneering stabilization strategies to advanced microenvironment engineering, enabling breakthroughs in oxygen reduction, hydrogen evolution, and CO₂ reduction. SACs maximize atom utilization but face multi-step reaction limits, addressed by DACs through synergistic dual-site mechanisms. PSMSCs further enhance activity via ordered atomic arrangements, ensuring uniform active sites and mechanistic clarity. Key breakthroughs include microenvironment engineering to tailor active sites, as well as advanced characterization techniques revealing dynamic restructuring under operando conditions. The transition from isolated atoms to ordered ensembles highlights the importance of atomic-level control in unlocking new catalytic mechanisms. This work underscores the transformative potential of ADCs in sustainable energy technologies and provides a roadmap for future research in rational catalyst design, dynamic behavior analysis, and scalable synthesis. Full article

(This article belongs to the Section Energy and Catalysis)

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55 pages, 12018 KiB

Open AccessReview

Antimicrobial Nanotubes: From Synthesis and Promising Antimicrobial Upshots to Unanticipated Toxicities, Strategies to Limit Them, and Regulatory Issues

by Silvana Alfei and Gian Carlo Schito

Nanomaterials 2025, 15(8), 633; https://doi.org/10.3390/nano15080633 - 21 Apr 2025

Abstract

Nanotubes (NTs) are nanosized tube-like structured materials made from various substances such as carbon, boron, or silicon. Carbon nanomaterials (CNMs), including carbon nanotubes (CNTs), graphene/graphene oxide (G/GO), and fullerenes, have good interatomic interactions and possess special characteristics, exploitable in several applications because of [...] Read more.

Nanotubes (NTs) are nanosized tube-like structured materials made from various substances such as carbon, boron, or silicon. Carbon nanomaterials (CNMs), including carbon nanotubes (CNTs), graphene/graphene oxide (G/GO), and fullerenes, have good interatomic interactions and possess special characteristics, exploitable in several applications because of the presence of sp2 and sp3 bonds. Among NTs, CNTs are the most studied compounds due to their nonpareil electrical, mechanical, optical, and biomedical properties. Moreover, single-walled carbon nanotubes (SWNTs) have, in particular, demonstrated high ability as drug delivery systems and in transporting a wide range of chemicals across membranes and into living cells. Therefore, SWNTs, more than other NT structures, have generated interest in medicinal applications, such as target delivery, improved imaging, tissue regeneration, medication, and gene delivery, which provide nanosized devices with higher efficacy and fewer side effects. SWNTs and multi-walled CNTs (MWCNTs) have recently gained a great deal of attention for their antibacterial effects. Unfortunately, numerous recent studies have revealed unanticipated toxicities caused by CNTs. However, contradictory opinions exist regarding these findings. Moreover, the problem of controlling CNT-based products has become particularly evident, especially in relation to their large-scale production and the nanosized forms of the carbon that constitute them. Important directive rules have been approved over the years, but further research and regulatory measures should be introduced for a safer production and utilization of CNTs. Against this background, and after an overview of CNMs and CNTs, the antimicrobial properties of pristine and modified SWNTs and MWCNTs as well as the most relevant in vitro and in vivo studies on their possible toxicity, have been reported. Strategies and preventive behaviour to limit CNT risks have been provided. Finally, a debate on regulatory issues has also been included. Full article

(This article belongs to the Special Issue Advances in Carbon Nanotubes: Synthesis, Properties, and Cutting-Edge Applications)

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15 pages, 3880 KiB

Open AccessArticle

Flexible Solar Interfacial Evaporators with Photocatalytic Function for Purification of High-Salinity Organic Wastewater

by Yucheng Li, Xia Zhao, Tao Hu, Lingxiao Li, Xiaopeng Huang and Junping Zhang

Nanomaterials 2025, 15(8), 632; https://doi.org/10.3390/nano15080632 - 21 Apr 2025

Abstract

Solar-driven interfacial water evaporation technology coupled with photocatalytic function is regarded as an emerging approach for treating high-salinity organic wastewater, but it remains challenging to design high-performance solar evaporators with excellent photocatalytic properties. Here, we designed a two-dimensional flexible solar interfacial evaporator with [...] Read more.

Solar-driven interfacial water evaporation technology coupled with photocatalytic function is regarded as an emerging approach for treating high-salinity organic wastewater, but it remains challenging to design high-performance solar evaporators with excellent photocatalytic properties. Here, we designed a two-dimensional flexible solar interfacial evaporator with photocatalytic function for the purification of high-salinity organic wastewater. The solar evaporator was prepared by the deposition of Cu-based metal organic frameworks (Cu-MOFs) onto a polyester fabric by solvothermal reaction, during which graphitic carbon nitride was also deposited as carried by Cu-MOFs. The solar evaporator achieves an outstanding evaporation rate of 1.95 kg m⁻² h⁻¹ for simulated seawater (3.5 wt% NaCl) under 1 sun. The evaporator also shows efficient evaporation performance and salt resistance for high-concentration saline water due to its outstanding water transport capacity and efficient light absorption ability. Furthermore, salt ions and organic pollutants can be simultaneously removed from high-salinity organic wastewater by the evaporator due to the synergistic effects of adsorption, the photothermal effect and photocatalytic performance. This study successfully integrated photocatalytic technology with solar-driven interfacial evaporation, extending the multifunctionality of solar evaporators for treating high-salinity organic wastewater. Full article

(This article belongs to the Section Energy and Catalysis)

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31 pages, 7019 KiB

Open AccessReview

Intelligent Systems for Inorganic Nanomaterial Synthesis

by Chang’en Han, Xinghua Dong, Wang Zhang, Xiaoxia Huang, Linji Gong and Chunjian Su

Nanomaterials 2025, 15(8), 631; https://doi.org/10.3390/nano15080631 - 21 Apr 2025

Abstract

Inorganic nanomaterials are pivotal foundational materials driving traditional industries’ transformation and emerging sectors’ evolution. However, their industrial application is hindered by the limitations of conventional synthesis methods, including poor batch stability, scaling challenges, and complex quality control requirements. This review systematically examines strategies [...] Read more.

Inorganic nanomaterials are pivotal foundational materials driving traditional industries’ transformation and emerging sectors’ evolution. However, their industrial application is hindered by the limitations of conventional synthesis methods, including poor batch stability, scaling challenges, and complex quality control requirements. This review systematically examines strategies for constructing automated synthesis systems to enhance the production efficiency of inorganic nanomaterials. Methodologies encompassing hardware architecture design, software algorithm optimization, and artificial intelligence (AI)-enabled intelligent process control are analyzed. Case studies on quantum dots and gold nanoparticles demonstrate the enhanced efficiency of closed-loop synthesis systems and their machine learning-enabled autonomous optimization of process parameters. The study highlights the critical role of automation, intelligent technologies, and human–machine collaboration in elucidating synthesis mechanisms. Current challenges in cross-scale mechanistic modeling, high-throughput experimental integration, and standardized database development are discussed. Finally, the prospects of AI-driven synthesis systems are envisioned, emphasizing their potential to accelerate novel material discovery and revolutionize nanomanufacturing paradigms within the framework of AI-plus initiatives. Full article

(This article belongs to the Section Inorganic Materials and Metal-Organic Frameworks)

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14 pages, 3125 KiB

Open AccessArticle

Mechanical Improvement of Graphene Oxide Film via the Synergy of Intercalating Highly Oxidized Graphene Oxide and Borate Bridging

by Yiwei Quan, Peng He and Guqiao Ding

Nanomaterials 2025, 15(8), 630; https://doi.org/10.3390/nano15080630 - 20 Apr 2025

Abstract

Converting graphene oxide (GO) nanosheets into high-performance paper-like GO films has significant practical value. However, it is still challenging because the mechanical properties significantly decreased when the nanosheets are assembled into films. The simultaneous attainment of high tensile strength, high modulus, and relatively [...] Read more.

Converting graphene oxide (GO) nanosheets into high-performance paper-like GO films has significant practical value. However, it is still challenging because the mechanical properties significantly decreased when the nanosheets are assembled into films. The simultaneous attainment of high tensile strength, high modulus, and relatively high toughness remains a formidable challenge. Here, we demonstrated an effective approach involving the incorporation of high oxidized graphene oxide (HOGO) and borate, to enhance the mechanical properties of GO films. X-ray photoelectron spectroscopy (XPS) measurements and thermogravimetric analysis-differential scanning calorimetry (TG-DSC) revealed the synergistic effects of hydrogen and covalent bonding from HOGO and borate, respectively. Additionally, wide-angle X-ray scattering (WAXS) analysis indicated a notable enhancement in the orientation of the GO in the resulting films, characterized by the Herman’s orientation factor (ƒ = 0.927), attributable to the combined action of hydrogen and covalent bonding. The borate-crosslinked GO+HOGO films exhibited exceptional mechanical properties, with an impressive strength (417.2 MPa), high modulus (43.8 GPa), and relatively high toughness (2.5 MJ m⁻³). This innovative assembly strategy presents a promising avenue for achieving desirable mechanical properties, thereby enhancing the potential for commercial applications. Full article

(This article belongs to the Topic Advances in Carbon-Based Materials)

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27 pages, 7566 KiB

Open AccessArticle

Toxicological Effects of Silver-Modified Bentonite Nanocomposites on Microalgae: Impact on Cell Growth, Antioxidant Enzymes, and Gene Expression

by Oumayma Ghariani, Jihen Elleuch, Anna Maria Ferretti, Stefano Econdi, Chiara Bisio, Philippe Michaud, Imen Fendri, Matteo Guidotti and Slim Abdelkafi

Nanomaterials 2025, 15(8), 629; https://doi.org/10.3390/nano15080629 - 20 Apr 2025

Abstract

The increasing use of nanostructured silver-containing inorganic materials raises concerns about their impact on aquatic organisms. This study assessed the toxicity of silver-modified bentonite composites on Chlamydomonas sp. Two materials were tested: silver-exchanged bentonite (Ben-Ag) and its reduced form (Ben-Ag (H₂)).Microalgae [...] Read more.

The increasing use of nanostructured silver-containing inorganic materials raises concerns about their impact on aquatic organisms. This study assessed the toxicity of silver-modified bentonite composites on Chlamydomonas sp. Two materials were tested: silver-exchanged bentonite (Ben-Ag) and its reduced form (Ben-Ag (H₂)).Microalgae were exposed to 0.5 IC₅₀, 1.5 IC₅₀, and 2 IC₅₀. Ben-Ag showed higher toxicity than Ben-Ag (H₂), which even promoted algal growth at low doses. Fluorescence microscopy revealed morphological shrinkage in treated cells. Increased phenol content, elevated malondialdehyde (MDA) levels, and altered antioxidant enzyme activities further confirmed Ben-Ag toxicity, along with reduced growth and photosynthetic pigments. Transcriptomic analysis revealed significant changes in gene expression under Ben-Ag exposure. Genes involved in photosynthesis (petB, psbL), caspase activity (casp), and carotenoid metabolism (Q2CHY) were down-regulated, indicating stress-induced damage. In contrast, genes encoding stress response enzymes (SOD, peroxidase), carbon metabolism enzymes (rbcL, PGQ1), and β-carotene biosynthesis (Q2BKT) were up-regulated, reflecting cellular defense mechanisms. Overall, the study highlights the high toxicity of Ben-Ag to Chlamydomonas sp., emphasizing the importance of evaluating environmental risks before using such materials in aquatic environments. Full article

(This article belongs to the Section Nanocomposite Materials)

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14 pages, 4138 KiB

Open AccessArticle

First-Principles Study on the CO₂ Reduction Reaction (CO₂RR) Performance of h-BN-Based Single-Atom Catalysts Modified with Transition Metals

by Xiansheng Yu, Can Zhao, Qiaoyue Chen, Lai Wei, Xucai Zhao, Lili Zhang, Liqian Wu and Yineng Huang

Nanomaterials 2025, 15(8), 628; https://doi.org/10.3390/nano15080628 - 20 Apr 2025

Abstract

The reasonable design of low-cost, high-activity single-atom catalysts (SACs) is crucial for achieving highly efficient electrochemical CO₂RR. In this study, we systematically explore, using density functional theory (DFT), the performance of transition metal (TM = Mn, Fe, Co, Ni, Cu, Zn)-doped [...] Read more.

The reasonable design of low-cost, high-activity single-atom catalysts (SACs) is crucial for achieving highly efficient electrochemical CO₂RR. In this study, we systematically explore, using density functional theory (DFT), the performance of transition metal (TM = Mn, Fe, Co, Ni, Cu, Zn)-doped defect-type hexagonal boron nitride (h-BN) SACs TM@B₋₁N (B vacancy) and TM@BN₋₁ (N vacancy) in both CO₂RR and the hydrogen evolution reaction (HER). Integrated crystal orbital Hamiltonian population (ICOHP) analysis reveals that these catalysts weaken the sp orbital hybridization of CO₂, which promotes the formation of radical-state intermediates and significantly reduces the energy barrier for the hydrogenation reaction. Therefore, these theoretical calculations indicate that the Mn, Fe, Co@B₋₁N, and Co@BN₋₁ systems demonstrate excellent CO₂ chemical adsorption properties. In the CO₂RR pathway, Mn@B₋₁N exhibits the lowest limiting potential (U_L = −0.524 V), and its higher d-band center (−0.334 eV), which aligns optimally with the adsorbate orbitals, highlights its excellent catalytic activity. Notably, Co@BN₋₁ exhibits the highest activity in HER, while U_L is −0.217 V. Furthermore, comparative analysis reveals that Mn@B₋₁N shows 16.4 times higher selectivity for CO₂RR than for HER. This study provides a theoretical framework for designing bifunctional SACs with selective reaction pathways. Mn@B₋₁N shows considerable potential for selective CO₂ conversion, while Co@BN₋₁ demonstrates promising prospects for efficient hydrogen production. Full article

(This article belongs to the Special Issue Semiconductor-Based Nanomaterials for Catalytic Applications)

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