High-resolution Electron Microscopy Research Articles

Atomic-Scale Distribution and Evolution of Strain in Pt Nanoparticles Grown on MoS2 Nanosheet.

Interface strain significantly affects the band structure and electronic states of metal-nanocrystal-2D-semiconductor heterostructures, impacting system performance. While transmission electron microscopy (TEM) is a powerful tool for studying interface strain, its accuracy may be compromised by sample overlap in high-resolution images due to the unique nature of the metal-nanocrystals-2D-semiconductors heterostructure. Utilizing digital dark-field technology, the substrate influence on metal atomic column contrasts is eliminated, improving the accuracy of quantitative analysis in high-resolution TEM images. Applying this method to investigate Pt on MoS2 surfaces reveals that the heterostructure introduces a tensile strain of ≈3% in Pt nanocrystal. The x-directional linear strain in Pt nanocrystals has a periodic distribution that matches the semi-coherent interface between Pt nanocrystals and MoS2, while the remaining strain components localize mainly on edge atomic steps. These results demonstrate an accurate and efficient method for studying interface strain and provide a theoretical foundation for precise heterostructure fabrication.

Copper nanoparticles biosynthesis by Stevia rebaudiana extract: biocompatibility and antimicrobial application.

The growth of material science and technology places a high importance on the creation of better processes for the synthesis of copper nanoparticles. So that, an easy, ecological, and benign process for producing copper nanoparticles (CuNPs) has been developed using candy leaf (Stevia rebaudiana) leaves aqueous extract for the first time. UV-visible spectroscopy, dynamic light scattering (DLS), X-ray diffraction (XRD), high-resolution transmission electron microscope (HR-TEM), Fourier transmission infrared (FTIR), and zeta potential were applied to demonstrate strong characterization for the biosynthesized stevia-CuNPs. The UV-visible absorbance at 575nm of surface plasmon resonance (SPR) was 1.2. The particle size mean diameter was recorded as 362.3nm with - 10.8 mV zeta potential. The HR-TEM scanning revealed 51.46-53.17nm and spherical-shaped stevia-CuNPs surrounded by coat-shell proteins. The cytotoxicity and cytocompatibility activity assay revealed that stevia-CuNPs was safe in lower concentrations and had a significant cell viability reduction in higher concentrations. The produced stevia-CuNPs were applied as antimicrobial agents against eight pathogenic bacteria and five fungi strains. The inhibitory action of the stevia-CuNPs was more pronounced in bacteria than in fungi, and they likewise demonstrated further inhibition zones in Staphylococcus aureus (50.0mm) than in Aspergillus flavus (55.0mm). With inhibition zone sizes of 50.0mm and 47.0mm and 50µg/ml minimum inhibitory concentration, S. aureus and A. flavus were the most inhibited pathogens. The minimum lethal effect (MLC) estimate for S. aureus was 50µg/ml, whereas 75µg/ml for A. flavus. The stevia-CuNPs mode of action was characterized as bactericidal/fungicidal as the ratio of MIC to MLC was estimated to be equal to or less than 2. After all, stevia-CuNPs could be used as an alternative to commercial antibiotics to solve the problem of multidrug-resistant (MDR) microorganisms.

Microhardness, Surface Roughness, and Wear Resistance Enhancement of Reinforced Conventional Glass Ionomer Cement Using Fluorinated Graphene Oxide Nanosheets.

Conventional glass ionomer cements (GICs) have been considered the most prevalent restorative material however; the reduced mechanical qualities and decreased wear resistance have been the main challenges facing their wide clinical application. This study was designed to assess the mechanical properties of fluorinated graphene (FG) oxide-modified conventional GIC. Composites of FG/GIC samples were prepared using (Medifil from PROMEDICA, Germany, shade A3) at different concentrations (0wt%) control group and (1wt%, 2wt% and 3wt% FG) groups using cylindrical molds (3mm × 6mm). FG was prepared using hydrothermal technique and characterized using XPERT-PRO Powder Diffractometer system for X-ray diffraction analysis and JEOL JEM-2100 high resolution transmission electron microscope. Vickers' hardness and wear resistance of GI samples were measured. Mechanical abrasion was performed via three-body tooth brushing wear test using ROBOTA chewing simulator coupled with a thermocycling protocol (Model ACH-09075DC-T, AD-Tech Technology Co., Ltd., Leinfelden-Echterdingen, Germany). Comparisons between groups with respect to normally distributed numeric variables were performed using one-way analysis of variance test followed by posthoc test. While paired t-test was utilized for comparing data within the same group. The surface roughness values of GICs (1wt% FG) and (2wt% FG) composites were significantly lower than those of the control and 3wt%FG groups. Vickers' hardness numbers were significantly higher in FG/GICs composites than in the control group (p≤0.05). GIC/FG combinations have sufficient strength to resist the occlusion stresses with improved hardness as compared with conventional GIC. GIC/FG appeared to be a promising restorative material.

A Highly Sensitive and Selective Fluorescent Sensor for Folic Acid Detection Based on D-penicillamine Stabilized Ag/Cu Alloy Nanoclusters.

In this work, a highly sensitive and selective method for detecting folic acid (FA) was developed using D-penicillamine (DPA) stabilized Ag/Cu alloy nanoclusters (DPA@Ag/Cu NCs). The yellow emission of DPA@Ag/Cu NCs was found to be quenched upon the addition of FA to the system. The fluorescence intensity quenching value demonstrated a linear relationship with FA concentrations ranging from 0.01 to 1200 μM,with a limit of detection(LOD) of 5.3 nM. Furthermore, the detection mechanism was investigated through various characterization analyses, including high resolution transmission electron microscopy, fluorescence spectra, ultraviolet-visible absorption spectra, and fluorescence lifetime. The results indicated that the fluorescence quenching induced by FA was a result of electron transfer from FA to the ligands of DPA@Ag/Cu NCs.The selectivity of the FA sensor was also evaluated, showing that common amino acids and inorganic ions had minimal impact on the detection of FA. Moreover, the standard addition method was successfully applied to detect FA in human serum, chewable tablets and FA tablets with promising results. The use of DPA@Ag/Cu NCs demonstrates significant potential for detecting FA in complex biological samples.

Tuning the End Alkyl Chain of the Ether Solvent to Stabilize the Electrode/Electrolyte Interfaces in the NCM-Li Battery.

Lithium metal batteries (LMBs) combined with a high-voltage nickel-rich cathode show great potential in meeting the growing need for high energy density. The lack of advanced electrolytes has been a major obstacle in the commercialization of high-voltage lithium metal batteries (LMBs), as these electrolytes need to effectively support both a stable lithium metal anode (LMA) and a high-voltage cathode (>4 V vs Li+/Li). In this work, by extending the two terminal methyl groups in DIGDME and TEGDME to n-butyl groups, we design a new weakly solvating electrolyte (2 M LIFSI+TEGDBE) that enables the stable cycling of NMC83 (LiNi0.83Co0.12Mn0.05O2) cathodes. The NMC83 cell exhibits a high and stable Coulombic efficiency (CE) of over 99%, as well as capacity retention of approximately 99.8% after 100 cycles at 0.3 C. X-ray photoelectron spectroscopy analysis (XPS) and high-resolution transmission electron microscope (HRTEM) images revealed that the anion species decomposed first, resulting in the formation of a cathode-electrolyte interface (CEI) film predominantly consisting of decomposition products from the anions on the positive electrode surface. This work links the functional group of solvents with the solvation structure and electrochemical performance of ether-based electrolytes, providing a distinctive sight to design advanced electrolytes for high-energy-density LMBs.

Synthesis and Physical Properties of the Misfit Layered Compound (EuS)1.13(NbSe2)2.

A new misfit layered compound with the stoichiometry (EuS)1+δ(NbSe2)2 (δ ≈ 0.13) has been successfully synthesized. High-resolution transmission electron microscopy and powder X-ray diffraction confirm the misfit structure with (EuS)-(EuS) spacing of 18.30(1) Å. Magnetization, electrical resistivity, heat capacity, and thermal transport measurements show that the material is a heavily doped semiconductor or poor metal with a low thermal conductivity of ∼1 W/m K and an antiferromagnetic ordering transition at TN = 4.7 K. In contrast to the parent materials, the misfit is neither ferromagnetic nor superconducting down to T = 0.4 K. We find evidence of a field-driven transition to a ferromagnetic state due to reorientation of ferromagnetic EuS layers at μoH = 0.5 T at T = 2 K.

Enhancing dye-sensitized solar cell performance: Optimizing Cu2ZnSnS4/ZnCo2O4 nanocomposites as efficient and cost-effective counter electrodes

This study investigates the utilization of Cu2ZnSnS4/ZnCo2O4 (CZTS/ZCO) nanocomposites prepared through hydrothermal and combustion methods as counter electrodes in Dye-Sensitized Solar Cells (DSSCs). Different ratios of Cu2ZnSnS4 and ZnCo2O4 were explored, and comprehensive analyses were conducted using X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), High-Resolution TEM (HRTEM), Brunauer–Emmett–Teller (BET) surface area analysis, Raman Spectroscopy, Electrochemical Impedance Spectroscopy (EIS), cyclic voltammetry (CV), Tafel analysis, Field Emission Scanning Electron Microscopy (FESEM), and Incident Photon-to-Electron Conversion Efficiency (IPCE), alongside long-term stability assessments. The CZTS:ZCO ratio of 2:1 exhibited the highest efficiency, reaching 8.81 %, with an open-circuit voltage of 729 mV, short-circuit current of 17.80 mAcm−2, and a fill factor of 67.9 %. This surpasses the efficiency of the reference Pt cell (8.42 %), which had an open-circuit voltage of 735 mV, short-circuit current of 17.16 mAcm−2, and a fill factor of 66.8 %. The average crystallite sizes for the main peaks of CZTS and ZCO samples were estimated to be 19.8 and 16.7 nm, respectively. The crystallite size can significantly affect the charge transfer and conductivity in the counter electrode during electrochemical processes; the presence of nanocrystals with these sizes can notably enhance the electrochemical properties and conductivity of the synthesized samples. Raman analysis results indicate that no additional phases or secondary phases such as ZnS and CuSnS3 have formed in the kesterite CZTS structure, and the crystal has formed as a single phase. Additionally, the F2g modes in the Raman spectrum of ZCO indicate tetrahedral units in the spinel ZCO structure, and the A1g modes represent octahedral structures in this phase, indicating the formation of suitable ZCO phase. The superior performance of the CZTS/ZCO nanocomposite can be attributed to its enhanced crystalline structure, superior charge transport characteristics, and improved electrocatalytic behaviours.

The Defects Genome of Janus Transition Metal Dichalcogenides.

Two-dimensional (2D) Janus Transition Metal Dichalcogenides (TMDs) have attracted much interest due to their exciting quantum properties arising from their unique two-faced structure, broken-mirror symmetry, and consequent colossal polarisation field within the monolayer. While efforts have been made to achieve high-quality Janus monolayers, the existing methods rely on highly energetic processes that introduce unwanted grain-boundary and point defects with still unexplored effects on the material's structural and excitonic properties Through High-resolution scanning transmission electron microscopy (HRSTEM), density functional theory (DFT), and optical spectroscopy measurements; this work introduces the most encountered and energetically stable point defects. It establishes their impact on the material's optical properties. HRSTEM studies show that the most energetically stable point defects are single (VS and VSe) and double chalcogen vacancy (VS -VSe), interstitial defects (Mi), and metal impurities (MW) and establish their structural characteristics. DFT further establishes their formation energies and related localized bands within the forbidden band. Cryogenic excitonic studies on h-BN-encapsulated Janus monolayers offer a clear correlation between these structural defects and observed emission features, which closely align with the results of the theory. The overall results introduce the defect genome of Janus TMDs as an essential guideline for assessing their structural quality and device properties. This article is protected by copyright. All rights reserved.

Abnormally High Graphitic Crystallization of Cellulose Nanocrystals.

Cellulose nanocrystals (CNCs) are currently of great interest for many applications, such as energy storage and nanocomposites, because of their natural abundance. A number of carbonization studies have reported abnormal graphitization behavior of CNCs, although cellulose is generally known as a precursor for hard carbon (nongraphitizable carbon). Herein, we report a spray-freeze-drying (SFD) method for CNCs and a subsequent carbonization study to ascertain the difference in the structural development between the amorphous and crystalline phases. The morphological observation by high-resolution transmission electron microscopy of the carbonized SFD-CNC clearly shows that the amorphous and crystalline phases of CNC are attributed to the formation of hard and soft carbon, respectively. The results of a reactive molecular dynamics (RMD) study also show that the amorphous cellulose phase leads to the formation of fewer carbon ring structures, indicative of hard carbon. In contrast, the pristine crystalline cellulose phase has a higher density and thermal stability, resulting in limited molecular relaxation and the formation of a highly crystalline graphitic structure (soft carbon).

Electrochemical Performance of Polyaniline‐Polyvanadate‐Copper Nanomaterials for the Detection of Benzoic Acid

AbstractThe introduction of nanomaterials as modified electrode materials into the field of electrochemical sensing is expected to improve the reliability, sensitivity, selectivity and repeatability of electrochemical sensors in detecting pollutants in the water environment. In this study, copper vanadate nanomaterials (Cu3V2O7(OH)2·2H2O, referred to as CVO) and Cu3V2O7(OH)2·2H2O/polyyaniline (PANI) composite nanomaterials (referred to as CVO/PANI) were successfully prepared and characterized by Fourier transform infrared spectrum (FTIR), X‐ray traveling‐action (XRD), scanning electron microscopy (SEM) and high‐resolution transmission electron microscopy (HR‐TEM).The modified glassy carbon electrodes (GCE) with these two materials were used for the detection of benzoic acid (BA) and exhibited excellent electrochemical sensing performance. The results show that two pairs of semi‐reversible redox peaks exist in both CVO and CVO/PANI modified glassy carbon electrode (GCE) in BA solution. The linear range of CVO and CVO/PANI nanomaterials‐modified GCE was 0.01‐2 mM and 0.001‐2 mM, and the limits of detection were 2.16 µM and 0.41 µM, respectively. Polyaniline plays important role in the electrochemical responses of BA at CVO/PANI modified GCE. PANI enhancedthe intensities of CV peaks and electrochemical determination ability for BA.This article is protected by copyright. All rights reserved

CO2-Based Stable Porous Metal-Organic Frameworks for CO2 Utilization.

The transformation of carbon dioxide (CO2) into functional materials has garnered considerable worldwide interest. Metal-organic frameworks (MOFs), as a distinctive class of materials, have made great contributions to CO2 capture and conversion. However, facile conversion of CO2 to stable porous MOFs for CO2 utilization remains unexplored. Herein, we present a facile methodology of using CO2 to synthesize stable zirconium-based MOFs. Two zirconium-based MOFs CO2-Zr-DEP and CO2-Zr-DEDP with face-centered cubic topology were obtained via a sequential desilylation-carboxylation-coordination reaction. The MOFs exhibit excellent crystallinity, as verified through powder X-ray diffraction and high-resolution transmission electron microscopy analyses. They also have notable porosity with high surface area (SBET up to 3688 m2 g-1) and good CO2 adsorption capacity (up to 12.5 wt %). The resulting MOFs have abundant alkyne functional moieties, confirmed through 13C cross-polarization/magic angle spinning nuclear magnetic resonance and Fourier transform infrared spectra. Leveraging the catalytic prowess of Ag(I) in diverse CO2-involved reactions, we incorporated Ag(I) into zirconium-based MOFs, capitalizing on their interactions with carbon-carbon π-bonds of alkynes, thereby forming a heterogeneous catalyst. This catalyst demonstrates outstanding efficiency in catalyzing the conversion of CO2 and propargylic alcohols into cyclic carbonates, achieving >99% yield at room temperature and atmospheric pressure conditions. Thus, this work provides a dual CO2 utilization strategy, encompassing the synthesis of CO2-based MOFs (20-24 wt % from CO2) and their subsequent application in CO2 capture and conversion processes. This approach significantly enhances overall CO2 utilization.

Plant-assisted green preparation of silver nanoparticles using leaf extract of Dalbergia sissoo and their antioxidant, antibacterial and catalytic applications.

Plant-mediated preparation of silver nanoparticles (AgNPs) is thought to be a more economical and environmentally benign process in comparison to physical and chemical synthesis methods. In the present study, the aqueous leaf extract of Dalbergia sissoo was prepared and utilized to reduce silver ion (Ag+) during the green synthesis of silver nanoparticles (DL-AgNPs). The formation of DL-AgNPs was verified using UV-Vis spectra, exhibiting the surface plasmon resonance (SPR) band at around 450nm. FT-IR analysis revealed the kinds of phytochemicals that serve as reducing and capping agents while DL-AgNPs are being synthesized. Analysis of scanning electron microscope (SEM) and high-resolution transmission electron microscopy (HR-TEM) images verified the development of spherical and oval-shaped DL-AgNPs, with sizes ranging from 10 to 25nm. The stability and particle size distribution of synthesized DL-AgNPs were ensured by zeta potential and DLS (dynamic light scattering) investigations. Additionally, X-ray diffraction (XRD) analysis confirmed the crystalline nature of DL-AgNPs. In antioxidant experiments, DL-AgNPs demonstrated significant scavenging capacities of DPPH and ABTS radicals with EC50 values of 51.32 and 33.32μg/mL, respectively. The antibacterial activity of DL-AgNPs was shown to be significant against harmful bacteria, with a maximum zone of inhibition (21.5 ± 0.86mm) against Staphylococcus aureus. Furthermore, DL-AgNPs exhibited effective catalytic activity to degrade environment-polluting dyes (methylene blue, methyl orange, and Congo red) and toxic chemicals (p-nitrophenol). The results of all these studies suggested that DL-AgNPs made from the leaf extract of Dalbergia sissoo have merit for application in the environmental and biomedical fields.

Evaluating nickel removal efficacy of Filtralite under laboratory conditions: Implications for sustainable urban drainage systems

Our study deals with the critical issue of heavy metal pollution in urban runoff; we focused particularly on the threat posed by heavy metals such as nickel to living organisms and water resources owing to their toxicity at low concentrations and non-biodegradability. In this study, we evaluated the efficacy of Filtralite, a filtration medium with excellent hydraulic properties, in removing nickel from water through laboratory experiments and advanced simulation tools. We analysed the geochemical processes involved in nickel removal, including precipitation and adsorption. Importantly, we implemented an innovative approach for numerical modelling using HP1, by combining HYDRUS-1D and PHREEQC for modelling solute transport in porous media and geochemical reactions, respectively. The experimental results revealed that the Filtralite-laden column achieved a removal efficiency of 93.5 % for injected nickel. We observed a significant increase in the effluent pH from 7.0 to 11.5 during the interaction with Filtralite, affecting the solubility of the nickel phases. The model showed the highest nickel concentration in the initial column layers because of rapid chemical precipitation and adsorption upon contact with Filtralite. High-resolution scanning electron microscopy images confirmed the presence of amorphous precipitates around the soil particles, aligning with the changes in pH. This study contributes significantly to environmental engineering and urban water management by introducing an innovative numerical model in HP1 to accurately simulate the removal of nickel using Filtralite. These findings validate the efficiency of Filtralite in extracting nickel from aqueous solutions. Thus, Filtralite is a strong candidate for inclusion in sustainable urban drainage systems.

A novel green reducing agent for the synthesis of chromium oxide nanoparticles (Cr2O3 NPs) based on saffron by-products: Characterization and antioxidant activity

The production of nanomaterials using safe, biological and environmentally friendly methods is attracting increasing attention. In the present study, aqueous extracts of Moroccan saffron (Crocus sativus L) by-products were used for the first time as a green stabilizer and reductant agent to synthesize chromium oxide nanoparticles (Cr2O3NPs). The aqueous extract of saffron by-products was analyzed for phytochemical screening, while the green synthesized Cr2O3NPs were analyzed using high-resolution scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The antioxidant activity of Cr2O3NPs, aqueous chromium nitrate solution (Cr (NO3)), and aqueous extract of saffron by-products have been also investigated using 1,1-Diphenyl-2-picrylhydrazyl (DPPH) method. The results showed that the aqueous extract of saffron by-products used for the synthesis of Cr2O3NPs appeared to be rich in phenolic (2.32 mg GA / g dry weight), flavonoid (2.28 mg RE / g dry weight), and anthocyanin compounds (33.67 mg Delphinidin / L extract). The XRD analysis confirmed that the Cr2O3NPs have a particle size of 31 nm with a hexagonal crystal structure. SEM micrographs of Cr2O3NPs showed a homogenous distribution and spherical shape, while the EDX spectrum confirmed that Cr2O3NPs contain significant amount of Chromium (61,90 %), and oxygen atoms (36,55 %). Moreover, the presence of absorption bands characteristic of the alcohol group (3451 cm−1) and the aromatic rings (1639 cm−1) in the infrared spectrum of Cr2O3NPs, indicates that the secondary metabolites of the saffron plant were successfully active in reducing chromium ions to Cr2O3NPs. Besides, the antioxidant activity results showed that the biosynthesized Cr2O3NPs exhibited strong inhibition percentages (63 %) compared to the aqueous extract of saffron by-products (74 %), and the aqueous solution of chromium nitrate (30 %) at 1,30 mg/mL. The study suggests that saffron by-products extract can be used as a natural reducing agent in the synthesis of Cr2O3NPs. Furthermore, the environmentally friendly synthesis process for Cr2O3NPs and their antioxidant effect make them suitable for use in various fields.

Cryo-EM combined with image deconvolution to determine ZIF-8 crystal structure

Abstract Metal-organic frameworks (MOFs) are crystalline porous materials with tunable properties, exhibiting great potential in gas adsorption, separation and catalysis.[1, 2] It is challenging to visualize MOFs with transmission electron microscopy (TEM) due to their inherent instability under electron beam irradiation. Here, we employ cryo-electron microscopy (cryo-EM) to capture images of MOF ZIF-8, revealing inverted-space structural information at a resolution of up to about 1.7 Å and enhancing its critical electron dose to around 20 e-/Å2. In addition, it is confirmed by electron-beam irradiation experiments that the high voltage could effectively mitigate the radiolysis, and the structure of ZIF-8 is more stable along the [100] direction under electron beam irradiation. Meanwhile, since the high-resolution electron microscope images is modulated by contrast transfer function (CTF) and it is difficult to determine the positions corresponding to the atomic columns directly from the images. We employ image deconvolution to eliminate the impact of CTF and obtain the structural images of ZIF-8. As a result, the heavy atom Zn and the organic imidazole ring within the organic framework can be distinguished from structural images.

Novel green synthesis of Value-Added graphene quantum dots from bagasse and pith for biological applications

The continuing rush for potential biomedical applications has sparked the fabrication of graphene quantum dots (GQDs) particularly from agricultural waste. GQDs are unique among carbon-based nanomaterials due to their flexibility, chemical stability, size control, and non-toxic nature. In this study, we have developed Graphene Quantum dots from sugarcane bagasse (GQDs-SB) and sugarcane bagasse pith (GQDs-SBP) by carbonization followed by microwave pyrolysis. The optical properties of the synthesized GQDs-SB and GQDs-SBP were characterized by Ultraviolet–Visible spectroscopy and Photoluminescence (PL) analysis and the surface functional groups were determined by FT- IR analysis. The High resolution transmission electron microscopy (HR-TEM) was used to examine dimensions and structure of GQDs-SB and GQDs-SBP. The storage stability of GQDs-SB and GQDs-SBP was monitored using Ultraviolet–Visible spectroscopy. The synthesized GQDs-SB and GQDs-SBP were evaluated for biological applications like anti-oxidant activity, anti inflammatory activity and cytotoxic effect was also assessed. GQDs-SB and GQDs-SBP demonstrated significant antioxidant and anti-inflammatory effects due to their great ability to scavenge free radicals and extraordinary water solubility. The synthesized GQDs-SB and GQDs-SBP were less toxic in nature.

Tri-reforming of methane over Ni/ZrO2 catalyst derived from Zr-MOF for the production of synthesis gas.

The increasing concentration of CO2 and CH4 in the environment is a global concern. Tri-reforming of methane (TRM) is a promising route for the conversion of these two greenhouse gases to more valuable synthesis gas with an H2/CO ratio of 1.5-2. In this study, a series of Zr-MOF synthesized via the solvothermal method and impregnation technique was used to synthesize the nickel impregnated on MOF-derived ZrO2 catalyst. The catalyst was characterized by various methods, including N2-porosimetry, X-ray diffraction (XRD), temperature programmed reduction (TPR), CO2-temperature programmed desorption (CO2-TPD), thermo-gravimetric analysis (TGA), chemisorption, field-emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM). Characterization results confirmed the formation of the Zr-MOF and nickel metal dispersed on MOF-derived ZrO2. Further, the tri-reforming activity of the catalyst developed was evaluated in a downflow-packed bed reactor. The various catalysts were screened for TRM activity at different temperatures (600-850°C). Results demonstrated that TRM was highly favorable over the NZ-1000 catalyst due to its desirable physicochemical properties, including nickel metal surface area (2.3 m2/gcat-1), metal dispersion (7.1%), and nickel metal reducibility (45%), respectively. Over the NZ-1000 catalyst, an optimum H2/CO ratio of ~ 1.6-2 was achieved at 750°C, and it was stable for a longer period of time.

Synergistic boost in Fe3O4 anode performance for li-ion batteries via Zn and Cu double doping and multi-walled carbon nanotube composite integration

In this study, a novel nanocomposite material comprising pure Fe3O4 (FO), doped Zn0.5Cu0.5Fe2O4-3 (ZCFO-3), and Zn0.5Cu0.5Fe2O4-3@ Multi-walled carbon nanotube (ZCFO-3@MWCNT) nanocomposite material is carefully prepared using a simple one-step hydrothermal process. Comprehensive surface and morphological analysis are conducted using X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), and High-resolution transmission electron microscopy (HRTEM), while compositional studies are investigated through Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The electrochemical performance is fully analyzed through Cyclic voltammetry (CV), Electrochemical impedance spectroscopy (EIS), rate capability tests, discharge/charge capacity, and cyclic stability evaluations. Among these three nanomaterials, ZCFO-3@MWCNT nanocomposite at 100 mA g−1 current density reveals the best performance, with a discharge capacity of 1974 mAh g–1, ZCFO-3 and FO reveal 1340 mAh g–1 and 1317 mAh g–1 respectively. After 800 cycles at 500 mA g−1 current density, ZCFO-3@MWCNT stays strong with a discharge capacity of 646 mAh g–1, while ZCFO-3 manages only 362 mAh g–1 and FO only 111 mAh g–1. After 1200 cycles at 500 mA g−1, the nanocomposite still delivers 518 mAh g–1. This study suggests that ZCFO-3@MWCNT could be a promising anode material for lithium-ion batteries.

Photocatalytic activity of polyaniline‐potassium doped nickel oxide nanocomposites: A comprehensive investigation on multifaceted properties

AbstractPolyaniline‐potassium doped nickel oxide nanocomposites (PANI/KNO) were efficiently synthesized via an in situ chemical oxidation method, meticulously confirmed by comprehensive x‐ray diffraction, Fourier transformation infrared spectroscopy, energy dispersive x‐ray spectroscopy, selected area electron diffraction, and x‐ray photoelectron spectroscopy analyses. The crystallite size and strain exhibited distinct behaviors, while field emission scanning electron microscopy revealed a blend of irregular spherical shapes and nanofibers, further confirmed by high resolution transmission electron microscopy. These composites exhibited significantly enhanced thermal stability, surpassing PANI by 1.39 times, and showcased a band gap exceeding 3 eV, along with multiple photoluminescence peaks at room temperature (RT). Moreover, their RT AC conductivity experienced a remarkable surge by 4.91 times compared to pure polyaniline. Jonscher's Power Law model and the Havriliak–Negami relaxation model are employed to elucidate the electrical properties of composite materials. The composites displayed nonDebye relaxation behavior with increased conductivity, as observed through impedance analysis, electrical modulus evaluation, and dielectric constant assessment. Additionally, evident superparamagnetic properties and multiple magnetic domains further contributed to their effectiveness. The PANI/KNO composite demonstrated photocatalytic efficiency, achieving over 90% degradation of methylene blue dye across four cycles, thus highlighting its superior photostability. Furthermore, investigations into its response to pH variations and scavenger activity underscored its immense potential for highly effective photocatalytic applications.

Oxidation-induced variations in the physical and fragmentation characteristics of exhaust soot from DMC-diesel blend: Effect of NO presence in the air atmosphere

This study investigated the changes in physical properties (including morphology, primary particle diameter, fractal dimension, and nanostructure) and fragmentation characteristics of exhaust soot from a modern direct injection diesel engine fueled with diesel (D100) and its blend with 7 vol% of dimethyl carbonate (DMC7) during oxidation processes in air and air-NO atmospheres. Soot particles (D100 soot and DMC7 soot) with specific oxidation degrees (0%, 20%, 50%, and 80%) were produced using a thermogravimetric analyzer, then applied to a high-resolution transmission electron microscopy to generate images. The results exhibited that the morphology for D100 soot and DMC7 soot transformed similarly through oxidation, experiencing an increase in fractal dimension, and a decrease in primary particle diameter, while the introduction of NO to the air accelerated these transformations. Additionally, the nanostructure of both soot particles was gradually ordered through oxidation, as evidenced by longer fringe length, narrower separation distance, and lower tortuosity, while DMC7 soot showed lower order degree compared to D100 soot. Interestingly, the ordering processes of soot nanostructure were decelerated as NO was involved in the oxidation process. Furthermore, the aggregate fragmentation rate for both soot particles declined over the oxidation process, while the possibility for primary particle fragmentation increased overall. Moreover, DMC7 soot exhibited significantly lower aggregate fragmentation rate and higher possibility for primary particle fragmentation than D100 soot at the same oxidation stage. This suggests that DMC7 soot is more susceptible to internal oxidation compared to D100 soot. Furthermore, the presence of NO in the air promoted aggregate fragmentation, while reducing the possibility of primary particle fragmentation.