Nanoscale Advances最新文献

Tandem neural networks for inverse design can only make single predictions, which limits the diversity of predicted structures. Here, we use conditional variational autoencoder (cVAE) for the inverse design of core–shell nanoparticles. cVAE is a type of generative neural network that generates multiple valid solutions for the same input condition. We generate a dataset from Mie theory simulations, including ten commonly used materials in plasmonic core–shell nanoparticle synthesis. We compare the performance of cVAE with that of the tandem model. Our cVAE model shows higher accuracy with a lower mean absolute error (MAE) of 0.013 compared to 0.046 for the tandem model. Robustness analysis with 100 test spectra confirms the improved reliability and diversity of cVAE. To validate the effectiveness of the cVAE model, we synthesize Au@Ag core–shell nanoparticles. cVAE model offers high accuracy in predicting material composition and spectral features. Our study shows the potential of cVAEs as generative neural networks in producing accurate, diverse, and robust nanoparticle designs.

Incorporating carbon-based fillers into triboelectric nanogenerators, TENGs, is a compelling strategy to enhance the power output. However, the lack of systematic studies comparing various carbon fillers and their impact on tribopositive contact layers necessitates further research. To address these concerns, various carbon fillers (including buckminsterfullerene (C₆₀), graphene oxide (GO), reduced graphene oxide (rGO), multi-wall carbon nanotube (MWCNT), and super activated carbon (SAC)) with distinct structural and electrical properties are mixed with polyvinyl alcohol, PVA, to form PVA-carbon composites and used as tribopositive layers in the contact-separation of TENGs. The results show that PVA-SAC provides the largest enhancements to the electrical outputs of the TENG. At the optimal loading of 1 wt%, PVA-SAC composites yielded a peak power density of 12.8 W m⁻², a substantial 220% enhancement compared to pristine PVA. The mechanism governing the enhancement is determined by analysing the changes in electrical and structural characteristics caused by the addition of various carbon fillers. Dielectric measurements indicated that enhanced dielectric properties did not significantly contribute to the observed increase in the triboelectric performance. Instead, Raman and FTIR analyses revealed a correlation between the PVA-carbon interactions and an increase in the D/G ratio of carbon fillers, accompanied by a reduction in hydrogen-bonded –OH groups within PVA. This suggests that the interaction between the π electrons of sp² hybridized carbon atoms and the oxygen lone pairs in PVA inhibits hydrogen bond formation, leading to an increase in free –OH groups. Consequently, these free –OH groups enhanced the electron-donating capability and improved the tribopositive behaviour of the PVA-carbon composites. Our results proved that filler-matrix interactions are paramount in engineering high-performance TENGs by controlling the electron affinity of the triboelectric layers.

This study investigates the effectiveness of polyaniline oxide (PANI) nanoparticles as photocatalysts for the degradation of organic dyes under visible light irradiation. Known for their stability and adjustable conductivity, PANI nanoparticles were synthesized via a hydrothermal method using P123 surfactants, followed by calcination. The morphology, structural phase, and optical properties of the synthesized PANI materials were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR). Results indicated that the synthesized PANI nanoparticles agglomerated into spherical particles with an average size of 70–80 nm. The photocatalytic properties of PANI materials were evaluated by the decolorization of rhodamine B (RhB) and methylene blue (MB) under simulated sunlight irradiation. The PANI photocatalyst was found to be highly effective in removing MB dye, achieving a removal efficiency of approximately 97.09% with a rate constant of 2.08 × 10⁻² min⁻¹. In comparison, the removal efficiency for RhB was about 58.01%. Additionally, the mechanism behind the photocatalytic degradation of MB dye by PANI was investigated and discussed. The study highlights the photostability and reproducibility of PANI nanoparticles through recycling experiments, contributing to the development of sustainable photocatalytic materials for efficient water treatment.

Using the spectral energy density method, we predict the phonon scattering mean lifetimes of polycrystalline graphene (PC-G) having polycrystallinity only along the x-axis with seven different misorientation (tilt) angles at room temperature. Contrary to other studies on PC-G samples, our results indicate a strong dependence of the thermal conductivity (TC) on the tilt angles which we attribute to careful preparation of our grain boundaries-based samples without introducing any local strains and ensuring periodic boundary conditions for the supercells along the x and y axes. We also show that the square of the group velocity components along x and y axes and the phonon lifetimes are uncorrelated and the phonon density of states are almost the same for all samples with different tilt angles. Further, a distribution of the group velocity component along x or y axis as function of normal frequency is found to be exponentially decaying whereas that of the phonon lifetime showed piecewise constant function behavior with respect to the frequency. We provide parameters for these distribution functions and suggest another measure of the TC based on these distributions. Finally, we perform a size-dependent analysis for two tilt angles, 21.78° and 32.20°, and find that bulk TC components decrease by around 34% to 62% in comparison to the bulk TC values of the pristine graphene. Our analysis reveals intriguing insights into the interplay between grain orientation, phonon scattering and thermal conductivity in graphene.

This study introduces a novel and effective approach for the electrocatalytic oxidation of alcohols, showcasing the development of a highly active and cost-effective anode catalyst for methanol and ethanol. A dual-embedded Ni electrode, named (Ni@NATPhos/Ni), is based on a carbon paste electrode modified with natural phosphate impregnated with nickel ions. A layer of nickel nanoparticles was then added via electrochemical deposition, using a precise combination of wet impregnation and potentiostatic electrodeposition techniques. Characterization using XRD and TEM revealed the formation of crystalline structures such as nickel pyrophosphate (Ni₂P₂O₇) and orthophosphate (Ni₃(PO₄)₂), along with nickel hydroxides (Ni(OH)₂), resulting in well-distributed homogenous nickel nanosized particles of approximately 30 nm. The electrocatalytic performance of Ni@NATPhos/Ni was assessed and compared with an unmodified carbon paste electrode in alkaline media. With peak current densities of 110 mA cm⁻² for methanol and 83 mA cm⁻² for ethanol oxidation, the synthesized catalyst demonstrated significantly improved catalytic efficiency. After 500 CV cycles, the dual-embedded electrode Ni@NATPhos/Ni demonstrated excellent stability, retaining 70.33% and 61.58% of its initial current values for ethanol and methanol, respectively, and exhibiting high tolerance to intermediate species poisoning. Electrochemical impedance spectroscopy (EIS) conducted after stability testing revealed an increase in solution resistance, indicative of the complete oxidation of intermediate species in the alkaline solution. The synthesized Ni@NATPhos/Ni electrode emerges as a promising and robust catalyst for alcohol oxidation reactions, offering significant advancements in electrocatalytic efficiency and stability.

Water pollution from dyes in wastewater is a critical global issue, as these stable organic dyes resist biodegradation, posing serious threats to aquatic ecosystems. To address this situation, advanced photocatalysts have been developed. Here, NiFe₂O₄/g-C₃N₄ was synthesized for the photocatalytic degradation of Rhodamine B (RhB) dye in the presence of H₂O₂ and visible light. Physicochemical analysis results showed NiFe₂O₄ nanoparticles dispersed in the g-C₃N₄ matrix, with an upward trend in the saturation magnetization of CNFx as NiFe₂O₄ content rose. The surface area of CNF30 was 62.3 m² g⁻¹, outperforming both NiFe₂O₄ (23.2 m² g⁻¹) and g-C₃N₄ (48.5 m² g⁻¹). NiFe₂O₄/g-C₃N₄ could be reused up to four cycles, and efficiently catalyzed the degradation of nearly 98% RhB dye, showing a decreased rate of up to 95% COD. Through scavenger studies, the main role of ˙OH was demonstrated. Therefore, highly efficient and recyclable NiFe₂O₄/g-C₃N₄ can be a potential photocatalyst for degradation of dyes.

The field of peptide based supramolecular biomaterials is fast evolving. These types of constructs have been shown to find applications in the fields of bioimaging, drug delivery and scaffolds for chemical reactions. However, the community typically focuses on the use of two specific classes of structured peptides: α-helices and β-sheets, clearly neglecting a unique peptide secondary structure: the polyproline helix. Herein, we report the first design, synthesis and characterization of polyproline based metallo-peptide nanoparticles. We demonstrate that rationally engineered polyproline helices can assemble in a divergent manner, into two types of nanoparticles. We also demonstrate that the primary sequence of the functionalised polyproline peptide is crucial to ensure a controlled assembly. This work clearly demonstrates that polyproline helices can be a powerful tool to achieve supramolecular assemblies of complex and responsive bioinspired nanomaterials.

Expression of concern for ‘In situ growth of N-doped carbon nanotubes from the products of graphitic carbon nitride etching by nickel nanoparticles’ by Mariusz Pietrowski et al., Nanoscale Adv., 2024, 6, 1720–1726, https://doi.org/10.1039/D3NA00983A.

Copper-based nanoparticles (NPs) are highly valued for their wide-ranging applications, with particular significance in CO₂ reduction. However current synthesis methods encounter challenges in scalability, batch-to-batch variation, and high energy costs. In this work, we describe a novel continuous flow synthesis approach performed at room temperature to help address these issues, producing spherical, colloidally stable copper(II) oxide (CuO) NPs. This approach leverages stabilizing ligands like oleic acid, oleylamine, and soy-lecithin, a novel choice for CuO NPs. The automated flow platform facilitates facile, real-time parameter screening of Cu-based nanomaterials using optical spectroscopy, achieving rapid optimization of NP properties including size, size dispersity, and colloidal stability through tuning of reaction parameters. This study highlights the potential of continuous flow synthesis for efficient parameter exploration to accelerate understanding, optimization, and eventually enable scale-up of copper-based NPs. This promises significant benefits for various sectors, including energy, healthcare, and environmental conservation, by enabling reliable production with reduced energy and cost requirements.

Solid Co nanorod fillers were pushed out of multi-walled carbon nanotubes via electromigration and their behaviors were observed in situ by transmission electron microscopy. When a solid Co nanorod was pushed out, the portion outside the nanotube increased in diameter. The behavior of the plastic deformation depended on the crystal orientation of the Co nanorod filler. When the direction of the electron flow was reversed, the Co nanorod was pulled into the host nanotube. In one trial, the Co nanorod was split into two portions inside the nanotube near one of the electrodes.