X-ray Transmission Research Articles

Thermodynamics of Ga2O3 Heteroepitaxy and Material Growth Via Metal Organic Chemical Vapor Deposition.

Heteroepitaxy of gallium oxide (Ga2O3) is gaining popularity to address the absence of p-type doping, limited thermal conductivity of Ga2O3 epilayers, and toward realizing high-quality p-n heterojunction. During the growth of β-Ga2O3 on 4H-SiC (0001) substrates using metal-organic chemical vapor deposition, we observed formation of incomplete, misoriented particles when the layer was grown at a temperature between 650 °C and 750 °C. We propose a thermodynamic model for Ga2O3 heteroepitaxy on foreign substrates which shows that the energy cost of growing β-Ga2O3 on 4H-SiC is slightly lower as compared to sapphire substrates, suggesting similar high-temperature growth as sapphire, typically in the range of 850 °C-950 °C, that can be used for the growth of β-Ga2O3 on SiC. A two-step modified growth method was developed where the nucleation layer was grown at 750 °C followed by a buffer layer grown at various temperatures from 920 °C to 950 °C. 2θ-ω scan of X-ray diffraction (XRD) and transmission electron microscope images confirm the β-polymorph of Ga2O3 with dominant peaks in the (-201) direction. The buffer layer grown at 950 °C using a "ramp-growth" technique exhibits root-mean-square surface roughness of 3 nm and full width of half maxima of XRD rocking curve as low as 0.79°, comparable to the most mature β-Ga2O3 heteroepitaxy on sapphire, as predicted by the thermodynamic model. Finally, the interface energy of an average Ga2O3 island grown on 4H-SiC is calculated to be 0.2 J/m2 from the cross-section scanning transmission electron microscope image, following the Wulff-Kaishew theorem of the equilibrium island shape.

X-ray transmission imaging of waste printed circuit boards for value estimation in recycling using machine learning.

The growing amount of electronic waste is a global challenge: on one hand, it poses a threat to the environment as it may contain toxic or hazardous substances, on the other hand it is a valuable 'urban mine' containing metals like gold and copper. Thus, recycling of electronic waste is not only a measure to reduce environmental pollution but also economically reasonable as prices for raw materials are rising. Within electronic waste, printed circuit boards (PCBs) occupy a prominent position, as they contain most of the valuable material. One important step in the overall recycling process is the evaluation and the value estimation for further treatment of the waste PCBs (WPCBs). In this article, we introduce a method for value estimation of entire WPCBs based on component detection. The value of the WPCB is then predicted by the value of the detected components. This approach allows a flexible application to different situations. In the first step, we created a dataset and labelled the components of 104 WPCBs using different component classes. The component detection is performed on dual energy X-ray images by the deep neural object detection network 'YOLO v5'. The dataset is split into a training, validation and test subset and standard performance measures as precision, recall and F1-score of the component detection are evaluated. Representative samples from all component classes were selected and analysed for the valuable materials to provide the ground truth of the value estimation in the subsequent step.

Elastic modulus of β-Ga2O3 nanowires measured by resonance and three-point bending techniques.

Due to the recent interest in ultrawide bandgap β-Ga2O3 thin films and nanostructures for various electronics and UV device applications, it is important to understand the mechanical properties of Ga2O3 nanowires (NWs). In this work, we investigated the elastic modulus of individual β-Ga2O3 NWs using two distinct techniques - in-situ scanning electron microscopy resonance and three-point bending in atomic force microscopy. The structural and morphological properties of the synthesised NWs were investigated using X-ray diffraction, transmission and scanning electron microscopies. The resonance tests yielded the mean elastic modulus of 34.5 GPa, while 75.8 GPa mean value was obtained via three-point bending. The measured elastic moduli values indicate the need for finely controllable β-Ga2O3 NW synthesis methods and detailed post-examination of their mechanical properties before considering their application in future nanoscale devices.

Tuning the structural, optical and dielectric features of PMMA/PEO/PANi blend using nano MnFe2O4

This study aimed to incorporate MnFe2O4 nanoparticles into a nanocomposite blend of poly (methyl methacrylate, PMMA), polyethylene oxide (PEO), and polyaniline (PANi). The incorporation was achieved using straightforward, environmentally friendly, and cost-effective techniques. The structures of MnFe2O4 and PMMA/PEO/PANi/x wt % MnFe2O4 were examined using X-ray diffraction (XRD) and/or transmission electron microscopy (TEM) techniques. The diffused reflectance technique was employed to investigate the linear optical properties of all blends, including absorbance, transmittance, reflectance, extinction coefficient, linear refractive index, optical dielectric constant and optical conductivity. PMMA/PEO/PANi blend has direct and indirect energy gaps of 5.33 and 4.65 eV, respectively. As MnFe2O4 doping level increased to 2.5 wt%, the smallest direct and indirect energy gap values of 5.16 and 4.08 eV were obtained, respectively. The addition of 1 wt% MnFe2O4 to the blend increased the refractive index value at 600 nm to 2.24. Nonlinear optical parameters of PMMA/PEO/PANi/x wt% MnFe2O4 blends were calculated. The emitted colors and their purities of all blends were investigated as a function of MnFe2O4 concentration. The obtained results suggested that the PMMA/PEO/PANi/x wt% MnFe2O4 blends may be used in a variety of optoelectronic and storage applications.

MOF-derived Co2CuS4 nanoparticles with gold-decorated reduced graphene oxide for electrochemical determination of chloramphenicol in real samples

Despite the beneficial effects of antibiotics such as chloramphenicol (CAP), they exert some destructive impacts on human health. We designed an electrochemical sensor based on reduced graphene oxide (rGO)/Au/Co2CuS4 nanohybrid for determination of CAP in food and biological samples. The Co2CuS4 was synthesized from binuclear metal-organic framework (CoCu-BDC) through a two-step process. Nanohybrid was characterized by X-ray photoelectron spectroscopy and transmission electron microscopy. The rGO/Au/Co2CuS4 provides more active sites and good electrical conductivity to reduce charge transfer resistance and improve the electrocatalytic activity for determination of CAP. The prepared sensor has a wide linear range from 7 to 141 nM with a limit of detection of 2.5 nM and a limit of quantification of 21.92 nM. It also provided high selectivity and repeatability with a relative standard deviation of 2.6%. Stability studies showed that the electrode has acceptable performance with efficiency of 95% after 33 days.

Double perovskite Bi2FeMnO6/TiO2 thin film heterostructure device for neuromorphic computing

Multiferroic materials have important research significance in the fields of magnetic random-access memory, ferroelectric random-access memory, resistive random-access memory, and neuromorphic computing devices due to their excellent and diverse physical properties. In this work, a solution of Bi2FeMnO6 was prepared using a solution-based method, and an Au/Bi2FeMnO6/TiO2 heterostructure device was fabricated on a Si substrate. X-ray diffraction and transmission electron microscopy data indicate that the Bi2FeMnO6 films have hexagonal R3c symmetry structures. The Bi2FeMnO6 film exhibits ferroelectricity with a fine remanent polarization. In addition, the Bi2FeMnO6-based devices have excellent switching ratios of 6.37 × 105. A larger switching ratio can provide a multi-resistance state for the device, which is beneficial for the simulation of synapses. Hence, it effectively emulates excitatory postsynaptic currents, paired-pulse facilitation, and long-term plasticity of synapses and achieves recognition accuracy of 95% in neuromorphic computing. We report a promising material for the development of various nonvolatile memories and neuromorphic synaptic devices.

Quantum sized blue light emitting ZnO nanoparticles: Synthesis, characterization and biomedical applications

The synthesis of zinc oxide nanoparticles via the hydrolysis and condensation method is described in this study. Characterization of the synthesized nanoparticles through X-ray diffraction, optical absorption, photoluminescence, and transmission electron microscopy discloses highly stable particles with an exceptionally small and uniform size distribution, showing a discrete quantum size effect. These nanoparticles show robust blue emission and demonstrate potent antibacterial activity against a spectrum of pathogenic bacteria, making them capable candidates for combating infectious diseases. Additionally, they display noteworthy anti-cancer properties against HT-29 colon cancer cell lines. This dual functionality of the ZnO nanoparticles holds significant promise for the development of affordable therapies in biomedical applications, as well as for potential applications in electronics.

The development of titanium dioxide nanotube-supported CdTe catalysts for photocatalytic enzymatic glucose fuel cell and response surface methodology optimization

Energy is one of the critical needs for human life and well-being. Alternative energy sources are essential due to the increase in energy demand with the rise in population the development of industrialization, and the damage caused by fossil fuels to the environment. Fuel cells, an alternative energy source, are a clean and environmentally friendly technology that converts chemical energy into electrical energy. In this study, titanium dioxide (TiO2) nanotube (TNT)-support CdTe catalysts were synthesized by the wet impregnation (WI) method. Glucose oxidase (GOD) and laccase (LAC) enzymes were modified by incubation on CdTe/TNT catalysts. These enzymatic and non-enzymatic catalysts were characterized by scanning electron microscope-energy dispersive X-ray (SEM-EDX) and mapping, X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscope (TEM) analyses. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA) analyses were used to examine the activity, resistance, and stability of catalysts for enzymatic photocatalytic glucose electrooxidation. The 3 % CdTe(50-50)-TNT-GOD/GCE electrode exhibited the highest activity, resistance, and stability under UV illumination compared to other electrodes. The modification parameters of the electrodes, incubation time, amount of catalyst ink, and drying time were found to be 136.96 min, 8.94 µL, and 21.30 min with response surface method (RSM) analysis, respectively. The estimated specific activity value was obtained as 0.754 mA/cm2 under optimized conditions.

UV-Irradiation Effects on the Optical Properties of Polyvinyl Alcohol/Carboxymethyl Cellulose/Polyvinyl Pyrrolidone/Tin Chromium Disulphide Nanocomposite Films for their Application in Optoelectronic Devices

A nanocomposite (NC) film containing polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC) and polyvinyl pyrrolidone (PVP) polymers and tin chromium disulfide (Sn0.75Cr0.25S2) nanoparticles (NPs) was prepared using thermolysis and casting techniques. The prepared NPs were characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. The induced alterations in the optical and color properties of the prepared PVA/CMC/PVP/Sn0.75Cr0.25S2 NC film due to UV irradiation, within fluences ranging from 10 to 80 Joule/cm2 (J/cm2), were characterized via UV spectroscopy and the International Commission on Illumination (CIE) color changes techniques. As the UV fluence increased up to 80 J/cm2, the maximum fluence used, both the direct and indirect bandgaps decreased. We attribute this to the dominance of formed chain crosslinks that destroyed the ordered structure and, thus, increased the amorphous regions. The effect of UV irradiation on the absorbance, refractive index, real and imaginary dielectric parameters and optical conductivity of the NC samples were studied. Furthermore, the optical color changes between the pristine and the irradiated films were evaluated. The pristine NC film was uncolored. It showed significant color changes when irradiated with the UV radiation at increasing fluences up to 80 J/cm2. The changes in the optical properties of PVA/CMC/PVP/Sn0.75Cr0.25S2 NC film suggested its usage as a promising candidate for future optoelectronics characterization techniques.

Coalescence of Porous Coordination Cages into Crystalline and Amorphous Bulk Solids.

Discrete porous coordination cages are attractive as a solution processable material whose porosity is not predicated on a network structure. Here, we leverage the peripheral functionalization of these cage structures to obtain 12 novel, solution processable, porous coordination cages that afford crystalline and amorphous single-phase millimeter-scale monolithic bulk structures (six of each) upon solidification. These structures are based upon prototypal metal-organic polyhedra [Cu24(5-x-isophthalate)24] (where x = NH2, OH), wherein meta-substitution of linker ligands with acyl chloride or isocyanate moieties afforded amide and urethane functional groups, respectively. These porous cage structures were obtainable via direct synthesis between a metal salt and a ligand as well as postsynthetic modification of the cage and formed monoliths following centrifugation and drying of the product. We rationalize their self-assembly as colloidal packing of nanoscale cuboctahedral cages through weak interactions between their hydrophobic alkyl/aromatic surfaces. In general, amorphous solids were obtained via rapid precipitation from the mother liquor upon methanol addition, while crystalline solids could be obtained only following further chloroform and pyridine additions. The structure of the materials is confirmed via gas sorption and spectroscopic methods, while powder X-ray diffraction and transmission electron microscopy are used to determine the nature of these bulk solids.

Tailoring thermoelectric performance of n-type Bi2Te3 through defect engineering and conduction band convergence

Bi2Te3, an archetypical tetradymite, is recognised as a thermoelectric (TE) material of potential application around room temperature. However, large energy gap (ΔEc ) between the light and heavy conduction bands results in inferior TE performance in pristine bulk n-type Bi2Te3. Herein, we propose enhancement in TE performance of pristine n-type Bi2Te3 through purposefully manipulating defect profile and conduction band convergence mechanism. Two n-type Bi2Te3 samples, S1 and S2, are prepared by melting method under different synthesis condition. The structural as well as microstructural evidence of the samples are obtained through powder x-ray diffraction and transmission electron microscopic study. Optothermal Raman spectroscopy is utilized for comprehensive study of temperature dependent phonon vibrational modes and total thermal conductivity ( κ ) of the samples which further validates the experimentally measured thermal conductivity. The Seebeck coefficient value is significantly increased from 235 μVK−1 (sample S1) to 310 μVK−1 (sample S2). This is further justified by conduction band convergence, where ΔEc is reduced from 0.10 eV to 0.05 eV, respectively. To verify the band convergence, the double band Pisarenko model is employed. Large power factor (PF) of 2190 μWm−1K−2 and lower κ value leading to ZT of 0.56 at 300 K is gained in S2. The obtained PF and ZT value are among the highest values reported for pristine n-type bulk Bi2Te3. In addition, appreciable value of TE quality factor and compatibility factor (2.7 V−1) at room temperature are also achieved, indicating the usefulness of the material in TE module.

New PMMA-InP/ZnS nanohybrid coatings for improving the performance of c-Si photovoltaic cells

Abstract Luminescent down-shifting (LDS) nanohybrid films are considered a potential solution to match the absorption spectrum of photovoltaic (PV) cells with the AM1.5 solar spectrum. LDS films were prepared by spin-coating polymethyl methacrylate (PMMA) doped with indium phosphide/zinc sulfide (InP/ZnS) quantum dots (QDs). The effect of doping concentration was investigated using X-ray diffraction, thermogravimetric analysis, transmission, and fluorescence spectroscopy. The results demonstrated that all PMMA LDS nanohybrid films were amorphous and exhibited thermal and chemical stability for all the doping concentrations of QDs. The optimal doping concentration was 0.06 wt%, demonstrating a tunable emission of the highest fluorescence quantum yield of 92% and the lowest reabsorption effect. This film showed the maximum enhancement of the efficiency of c-Si PV cells by 24.28% due to the down-conversion of ultraviolet A (UVA) portion of solar spectrum (320–400 nm) to match the sensitivity of c-Si PV cells. The implications of these results are significant for advancing affordable and clean energy in alignment with important sustainable development goals.

Effect of Ti content on microstructure and properties of Cu/AgCuTi/Al2O3 brazed joints

In this study, four groups of Ag-Cu-Ti brazing powder with different Ti contents of 2 wt%, 3 wt%, 3.75 wt% and 4 wt% were prepared by vacuum atomization, and then modulated into brazing pastes. Brazing between oxygen-free copper and alumina ceramics with the brazing pastes and the wettability experiments of the brazing pastes on alumina were done by vacuum brazing process at 880℃ for 30 min. Microstructures and wettability of both the braze alloy and joints were analyzed by scanning electron microscope, energy dispersive X-ray spectrometer and transmission electron microscope, and shear strength of the joints was tested by self-designed fixture. Based on thermodynamic calculation and kinetic analysis, the relationship between the products of the reactive layer and the change of Ti content was plotted to explore the reaction and wetting mechanism of AgCuTi braze alloy on alumina ceramics. The results show that the content of Ti in AgCuTi braze alloy is the main factor affecting the brazing performance and wettability of the braze alloy by affecting the products of AgCuTi/Al2O3 reaction layer. The reaction layer consists of TiO when the Ti content is 2 wt%, the reaction layer comprises of TiO and Ti3Cu3O when the Ti content is 3 wt%, the reaction layer is made up of Ti3O2 and Ti3Cu3O when the Ti content is 3.75 wt%, and the reaction layer consists entirely of Ti3Cu3O when the Ti content is 4.6 wt%. With the increase of the Ti content within the range of 2–4.6 wt%, the wettability of the braze alloy on the alumina ceramics improved, and the shear strength of the Cu/AgCuTi/Al2O3 joints increased.

Constructing MoS2-based cathode materials for zinc ion batteries

Aqueous zinc-ion batteries have advantages of high safety, friendly environment, low cost, and can be applied to large-scale energy storage. To prepare high-performance cathode materials easily and quickly is still one of the development directions. Based on the principle that two-dimensional layered materials can be thinned layer-by-layer via mechanical force, the molybdenum disulfide (MoS2)-based cathodes are prepared by one-step ball milling. The shear force and shockwave generated during ball milling effectively promote the preparation of MoS2/V2O5 cathode materials. X-ray diffraction, Raman, and infrared tests confirm the presence of both MoS2 and V2O5 components in the prepared MoS2/V2O5. The presence of metallic phase 1T-MoS2 in the MoS2/V2O5 is confirmed by X-ray photoelectron spectroscopy and transmission electron microscopy. Via a charging conversion mechanism, the obtained MoO3/V2O5 cathode has a high capacity of 417.4 mAh g−1, good rate performance (83.6 mAh g−1 at 10 A g−1), high energy and power densities (83.6 Wh kg−1 at 10,032 W kg−1). This study provides a new idea for constructing two-dimensional material-based cathodes by ball milling.

Synergistic enhancement of oxygen vacancy enrichment and morphology regulation in CeO2-NiCo2O4 heterostructure catalysts for high-performance cathodes in direct borohydride-hydrogen peroxide fuel cells

Hydrogen peroxide (H2O2) emerges as a viable oxidant for fuel cells, necessitating the development of an efficient and cost-effective electrocatalyst for the hydrogen peroxide reduction reaction (HPRR). In this study, we synthesized a self-supporting, highly active HPRR electrocatalyst comprising two morphologically distinct components: CeO2-NiCo2O4 nanowires and CeO2-NiCo2O4 metal organic framework derivatives, via a two-step hydrothermal process followed by air calcination. X-ray diffraction and transmission electron microscopy analysis confirmed the presence of CeO2 and NiCo2O4, revealing the amalgamated interface between them. CeO2 exhibits multifunctionality in regulating the surface electronic configuration of NiCo2O4, fostering synergistic connections, and introducing oxygen deficiencies to enhance the catalytic efficacy in HPRR. Electrochemical measurements demonstrate a reduction current density of 789.9 mA·cm−2 at −0.8 V vs. Ag/AgCl. The assembly of direct borohydride-hydrogen peroxide fuel cell (DBHPFC) exhibits a peak power density of 45.2 mW·cm−2, demonstrating durable stability over a continuous operation period of 120 h. This investigation providing evidence that the fabrication of heterostructured catalysts based on CeO2 for HPRR is a viable approach for the development of high-efficiency electrocatalysts in fuel cell technology.

Atomic and electronic structures of domain boundaries in LaTiO3 thin films

Domain boundaries in perovskite oxides often exhibit abundant physical properties and phenomena. Here, epitaxial LaTiO3 thin films on (100) SrTiO3 substrates are prepared by pulsed-laser deposition. X-ray diffraction and transmission electron microscopy investigations reveal that the epitaxial LaTiO3 thin films have good crystallinity but a high density of domain boundaries. Atomic-scale scanning transmission electron microscopy observations reveal that two types of domain boundaries are formed in the LaTiO3 thin films. The type I domain boundaries are formed on the {100} crystal planes, while the type II domain boundaries on the {110} crystal planes. Electron energy-loss spectroscopy analyses suggest that the valence states of Ti ions at the type I domain boundaries are +3, while those at the type II domain boundaries are +4. First-principles calculations reveal that the bandgap decreases at both domain boundaries compared to the bulk. The carrier concentration at the type I domain boundaries is significantly higher than that of the bulk, while the carrier concentration at the type II domain boundaries is lower. These findings suggest that domain boundaries play an important role in tailoring the electrical properties of the LaTiO3 thin films, thereby promoting the potential applications and property modulation of related materials and devices.

Kinetic study of p-nitrophenol degradation with zinc oxide nanoparticles prepared by sol–gel methods

Three zinc oxides (ZnO A, B, C) with similar spherical morphology but different sizes are synthesized by sol–gel methods. A kinetic study is carried out on the photocatalytic activity of these three ZnO, through the degradation of p-nitrophenol (PNP). A mathematical model is developed and the rate constants of the three catalysts are determined. To understand the parameters influencing the kinetics, the catalysts are reduced to the surface of an isolated particle (assuming perfect dispersion conditions where all catalytic active sites are available) whose size is determined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). However, by considering the real case (not a perfect dispersion), it appears that the size of the aggregates induced by the synthesis methods play a more important role in the catalytic activity of the three ZnO samples than defects. A discussion on the formation of these aggregates highlights the importance of the synthesis parameters, like the solvent or the surfactant used to obtain a high dispersion. The dispersion plays a crucial role in photocatalytic efficiency, with kinetics three times higher for the catalyst with the best dispersion. Also, as shown by photoluminescence and X-ray photoelectron spectroscopy (XPS), the type and amount of defects play an important role in the photocatalytic performance. ZnO A and B show a defect peak at 620 nm whereas ZnO C shows a defect peak at 680 nm, suggesting a different type of defect on the surface of the catalyst that reduces the photocatalytic performance. Electron paramagnetic resonance (EPR) measurements are performed to identify the type of radicals involved in PNP degradation. The results show that the catalyst with the best dispersion produces the highest amount of hydroxyl radicals. Finally, photoluminescence and XPS analyses underline the type and the amount of defects for the three photocatalysts.

Crystallographic structure, antibacterial effect, and catalytic activities of fig extract mediated silver nanoparticles

Silver nanoparticles (Ag NPs) play a pivotal role in the current research landscape due to their extensive applications in engineering, biotechnology, and industry. The aim is to use fig (Ficus hispida Linn. f.) extract (FE) for eco-friendly Ag NPs synthesis, followed by detailed characterization, antibacterial testing, and investigation of bioelectricity generation. This study focuses on the crystallographic features and nanostructures of Ag NPs synthesized from FE. Locally sourced fig was boiled in deionized water, cooled, and doubly filtered. A color change in 45 mL 0.005 M AgNO3 and 5 mL FE after 40 min confirmed the bio-reduction of silver ions to Ag NPs. Acting as a reducing and capping agent, the fig extract ensures a green and sustainable process. Various analyses, including UV–vis absorption spectrophotometry (UV), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray spectroscopy (EDX) and Transmission electron microscopy (TEM) were employed to characterize the synthesized nanoparticles, and Gas chromatography-mass spectrometry (GC-MS) analysis of the fig extract revealed the presence of eleven chemicals. Notably, the Ag NPs exhibited a surface plasmon resonance (SPR) band at 418 nm, confirmed by UV analysis, while FTIR and XRD results highlighted the presence of active functional groups in FE and the crystalline nature of Ag NPs respectively. With an average particle size of 44.57 nm determined by FESEM and a crystalline size of 35.87 nm determined by XRD, the nanoparticles showed strong antibacterial activities against Staphylococcus epidermidis and Escherichia coli. Most importantly, fig fruit extract has been used as the bio-electrolyte solution to generate electricity for the first time in this report. The findings of this report can be the headway of nano-biotechnology in medicinal and device applications.

Exploring radiation damage in (Hf0.2Zr0.2Ta0.2Ti0.2Nb0.2)C high-entropy carbide ceramic: Integrating experimental and atomistic investigations

This study investigates the intricate mechanisms that govern irradiation damage in high-entropy ceramic materials. Specifically, we synthesized (Hf0.2Zr0.2Ta0.2Nb0.2Ti0.2)C high-entropy carbide ceramics (HECC) with a single-phase rock-salt structure using spark plasma sintering. These ceramics were then subjected to irradiation with 1.08 MeV C ions, resulting in a dose of 7.2 dpa (dpa: displacements per atom) at both room temperature (RT) and 500 °C. To understand the resulting damage structure, we analyzed bulk irradiated HECC samples using Grazing Incidence X-ray Diffraction (GIXRD) and Transmission Electron Microscope (TEM) at both irradiation temperatures. GIXRD analysis revealed an average tensile strain out-of-plane of 0.16% for RT irradiation and 0.14% for irradiation at 500 °C. In addition, TEM analysis identified a buried damaged band, approximately 970 nm thick, under both irradiation temperatures. By employing the bright field TEM imaging technique under kinematic two-beam conditions, dislocation loops of both a/3 〈111〉{111} and a/2 〈110〉{110} types within the damaged band were observed. Furthermore, our analysis indicated an increase in the average size of the total dislocation loops within the band from 1.2 nm to 1.4 nm as the density decreased. Importantly, no amorphization, precipitates, or voids were detected in the damaged band under both irradiation temperatures. Density functional theory (DFT) simulations indicated that carbon predominantly resides in 〈110〉 split interstitial sites causing lattice expansion, while vacancies, particularly Nb, induced compression along the c-axis. Carbon atoms tend to bond when collectively present in the <110> split interstitial sites, contributing to the formation of interstitial loops.

Led-induced deposition of Pt and Au NPs on carbon fibers: Developing a novel strategy for facile fabrication of electrocatalysts for enhanced methanol electrooxidation

In addressing the imperative of aligning materials science with sustainable development, our study introduces an innovative method for the simultaneous deposition of Pt and Au nanoparticles onto a carbon support. This research represents the pioneering application of the photodeposition process for synthesizing bimetallic nanoparticles on a carbon matrix. The comprehensive characterization of the resulting nanostructures involves various techniques, including field X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM), atomic force microscopy (AFM), energy-dispersive X-ray analysis (EDX), inductively coupled plasma atomic emission spectroscopy (ICP-OES), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetric techniques. Our findings reveal that the photodeposition method produces a homogeneous AuPt nanostructure, demonstrating superior electrocatalytic activity in methanol oxidation compared to the monometallic carbon fiber_Pt (CF_Pt) catalyst. These results emphasize the effectiveness of our novel approach in fabricating electrocatalysts with exceptional performance in methanol oxidation reactions.