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Highly active metal nanoparticles are desired to serve in high-temperature electrocatalysis, for example, in solid oxide electrochemical cells. Unfortunately, the low thermal stability of nanosized particles and the sophisticated interface requirement for electrode structures to support concurrent ionic and electronic transport make it hard to identify the exact catalytic role of nanoparticles embedded within complex electrode architectures. Here we present an accurate analysis of the reactivity of oxide electrodes boosted by metal nanoparticles, where all particles participate in the reaction. Monodisperse particles (Pt, Pd, Au and Co), 10 nm in size and stable at high temperature (more than 600 °C), are uniformly distributed onto mixed-conducting oxide electrodes as a model electrochemical cell via self-assembled nanopatterning. We identify how the metal catalysts activate hydrogen electrooxidation on the ceria-based electrode surface and quantify how rapidly the reaction rate increases with proper choice of metal. These results suggest an ideal electrode design for high-temperature electrochemical applications.The impact of metal nanoparticles on the reactivity of mixed-conducting oxide fuel cell electrodes is identified and quantified.

The conventional solid-state reaction suffers from low diffusivity, high energy consumption, and uncontrolled morphology. These limitations are competed by the presence of water in solution route reaction. Herein, based on concept of combining above methods, we report a facile solid-state reaction conducted in water vapor at low temperature along with calcium doping for modifying lithium vanadate as anode material for lithium-ion batteries. The optimized material, delivers a superior specific capacity of 543.1, 477.1, and 337.2 mAh g −1 after 200 and 1000 cycles at current densities of 100, 1000 and 4000 mA g −1 , respectively, which is attributed to the contribution of pseudocapacitance. In this work, we also use experimental and theoretical calculation to demonstrate that the enhancement of doped lithium vanadate is attributed to particles confinement of droplets in water vapor along with the surface and structure variation of calcium doping effect. The conventional solid-state reaction suffers from the low diffusivity, high energy consumption, and uncontrolled morphology. Here, the authors report a low-temperature solid-state reaction under water vapour for synthesis of various electrodes for lithium ions batteries.

Utilization of carbon dioxide (CO 2 ) molecules leads to increased interest in the sustainable synthesis of methane (CH 4 ) or methanol (CH 3 OH). The representative reaction intermediate consisting of a carbonyl or formate group determines yields of the fuel source during catalytic reactions. However, their selective initial surface reaction processes have been assumed without a fundamental understanding at the molecular level. Here, we report direct observations of spontaneous CO 2 dissociation over the model rhodium (Rh) catalyst at 0.1 mbar CO 2 . The linear geometry of CO 2 gas molecules turns into a chemically active bent-structure at the interface, which allows non-uniform charge transfers between chemisorbed CO 2 and surface Rh atoms. By combining scanning tunneling microscopy, X-ray photoelectron spectroscopy at near-ambient pressure, and computational calculations, we reveal strong evidence for chemical bond cleavage of O‒CO* with ordered intermediates structure formation of (2 × 2)-CO on an atomically flat Rh(111) surface at room temperature. Direct observation of carbon dioxide dissociation provides an origin of catalytic conversion for industrial chemical reactions. Here, the authors reveal their molecular interactions on the rhodium catalyst at near-ambient pressure by interface science techniques and computational calculations.

This paper demonstrates for the first time the fabrication of Zr-Cu alloy ingots from a Hf- free ZrO 2 precursor in a molten CaCl 2 medium to recover nuclear-grade Zr. The reduction of ZrO 2 in the presence of CaO was accelerated by the formation of Ca metal in the intermediate stage of the process. Tests conducted with various amounts of ZrO 2 indicate that the ZrO 2 was reduced to the metallic form at low potentials applied at the cathode, and the main part of the zirconium was converted to a CuZr alloy with a different composition. The maximum oxygen content values in the CuZr alloy and Zr samples upon using liquid Cu were less than 300 and 891 ppm, respectively. However, Al contamination was observed in the CuZr during the electroreduction process. In order to solve the Al contamination problem, the fabrication process of CuZr was performed using the metallothermic reduction process, and the produced CuZr was used for electrorefining. The CuZr alloy was further purified by a molten salt electrorefining process to recover pure nuclear-grade Zr in a LiF-Ba 2 ZrF 8 -based molten salt, the latter of which was fabricated from a waste pickling acid of a Zr clad tube. After the electrorefining process, the recovered Zr metal was fabricated into nuclear-grade Zr buttons through arc melting following a salt distillation process. The results suggest that the removal of oxygen from the reduction product is a key reason for the use of a liquid CaCu reduction agent.

The long-term association between mRNA-based coronavirus disease 2019 (COVID-19) vaccination and the development of autoimmune connective tissue diseases (AI-CTDs) remains unclear. In this nationwide, population-based cohort study involving 9,258,803 individuals, we aim to determine whether the incidence of AI-CTDs is associated with mRNA vaccination. The study spans over 1 year of observation and further analyses the risk of AI-CTDs by stratifying demographics and vaccination profiles and treating booster vaccination as time-varying covariate. We report that the risk of developing most AI-CTDs did not increase following mRNA vaccination, except for systemic lupus erythematosus with a 1.16-fold risk in vaccinated individuals relative to controls. Comparable results were reported in the stratified analyses for age, sex, mRNA vaccine type, and prior history of non-mRNA vaccination. However, a booster vaccination was associated with an increased risk of some AI-CTDs including alopecia areata, psoriasis, and rheumatoid arthritis. Overall, we conclude that mRNA-based vaccinations are not associated with an increased risk of most AI-CTDs, although further research is needed regarding its potential association with certain conditions. Previous studies have reported cases of new autoimmune disease onset in individuals who have been vaccinated against SARS-CoV2. In this population-based cohort study involving over 9 million individuals, the authors demonstrate that the risk of developing most autoimmune conditions examined did not increase following mRNA-based SARS-CoV2 vaccination.

We synthesized ZnO nanorods (NRs) using simple hydrothermal method, with the simultaneous incorporation of gallium (Ga) and indium (In), in addition, investigated the co-doping effect on the morphology, microstructure, electronic structure, and electrical/optical properties. The growth behavior of the doped NRs was affected by the nuclei density and polarity of the (001) plane. The c-axis parameter of the co-doped NRs was similar to that of undoped NRs due to the compensated lattice distortion caused by the presence of dopants that are both larger (In 3+ ) and smaller (Ga 3+ ) than the host Zn 2+ cations. Red shifts in the ultraviolet emission peaks were observed in all doped NRs, owing to the combined effects of NR size, band gap renormalization, and the presence of stacking faults created by the dopant-induced lattice distortions. In addition, the NR/p-GaN diodes using co-doped NRs exhibited superior electrical conductivity compared to the other specimens due to the increase in the charge carrier density of NRs and the relatively large effective contact area of (001) planes. The simultaneous doping of In and Ga is therefore anticipated to provide a broader range of optical, physical, and electrical properties of ZnO NRs for a variety of opto-electronic applications.

A key challenge in heterogeneous catalysis is to design atomically dispersed catalysts with high surface density, while simultaneously preventing agglomeration and promoting electronic metal-support interaction. Transition metal dichalcogenides (TMDs), such as platinum diselenide (PtSe 2 ), offer a promising solution due to their unique structural and electronic properties. This study proposes a catalyst design that utilizes atomically dispersed transition metal species within the topmost layer of TMD as catalytic reaction sites. The substantial presence of surface-exposed Pt species on PtSe 2 and their role as catalytic reaction sites are elucidated using operando ambient-pressure X-ray photoelectron spectroscopy. Moreover, significantly high O 2 coverage on PtSe 2 , achieved by mitigating the exclusive adsorption of carbon monoxide (CO), leads to enhanced CO oxidation performance. The characteristic d -band structure and resulting high O 2 coverage of PtSe 2 are further confirmed with density functional theory calculations. Overall, this study highlights the potential of densely distributed atomic transition metal on TMDs, which allows electronic metal-chalcogen interactions and diverse reaction mechanisms. A major challenge in heterogeneous catalysis is creating atomically dispersed catalysts with high surface density that resist agglomeration and enhance metal-support interactions. Here, the authors propose a design using atomically dispersed transition metal species in the top layer of transition metal dichalcogenides as active sites.

In this study, the properties of blue organic light-emitting diodes (OLEDs), employing quantum well-like structure (QWS) that includes four different blue emissive materials of 4,4′-bis(2,2′-diphenylyinyl)-1,1′-biphenyl (DPVBi), 9,10-di(naphth-2-yl)anthracene (ADN), 2-(N,N-diphenyl-amino)-6-[4-(N,N-diphenyl amine)styryl]naphthalene (DPASN), and bis(2-methyl-8-quinolinolate)-4-(phenyl phenolato) aluminum (BAlq), were investigated. Conventional QWS blue OLEDs composed of multiple emissive layers and charge blocking layer with lower highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy level, and devices with triple emissive layers for more significant hole-electron recombination and a wider region for exciton generation were designed. The properties of triple emissive layered blue OLEDs with the structure of indium tin oxide (ITO) /N,N′-diphenyl-N,N′-bis(1-naphthyl-phenyl)-(1,1′-biphenyl)-4,4′-diamine (NPB) (700 Ǻ)/X (100 Ǻ)/BAlq (100 Ǻ)/X (100 Ǻ)/4,7-diphenyl-1,10-phenanthroline (Bphen) (300 Ǻ)/lithium quinolate (Liq) (20 Ǻ)/aluminum (Al) (1,200 Ǻ) (X = DPVBi, ADN, DPASN) were examined. HOMO-LUMO energy levels of DPVBi, ADN, DPASN, and BAlq are 2.8 to 5.9, 2.6 to 5.6, 2.3 to 5.2, and 2.9 to 5.9 eV, respectively. The OLEDs with DPASN/BAlq/DPASN QWS with maximum luminous efficiency of 5.32 cd/A was achieved at 3.5 V.

The incorporation of doping elements in ZnO nanostructures plays an important role in adjusting the optical and electrical properties in optoelectronic devices. In the present study, we fabricated 1-D ZnO nanorods (NRs) doped with different In contents (0% ~ 5%) on p-GaN films using a facile hydrothermal method and investigated the effect of the In doping on the morphology and electronic structure of the NRs and the electrical and optical performances of the n-ZnO NRs/p-GaN heterojunction light emitting diodes (LEDs). As the In content increased, the size (diameter and length) of the NRs increased and the electrical performance of the LEDs improved. From the electroluminescence (EL) spectra, it was found that the broad green-yellow-orange emission band significantly increased with increasing In content due to the increased defect states (oxygen vacancies) in the ZnO NRs and consequently, the superposition of the emission bands centered at 415 nm and 570 nm led to the generation of white-light. These results suggest that In doping is an effective way to tailor the morphology and the optical, electronic and electrical properties of ZnO NRs, as well as the EL emission property of heterojunction LEDs.

Highlights Janus MoSSe-based floating-gate memory exhibits ultrafast charge-trapping dynamics and stable charge retention exceeding 10 8  s under low-voltage operation. The intrinsic out-of-plane dipole moment in Janus MoSSe effectively suppresses leakage current and enlarges the memory window, even with ultrathin h-BN tunneling layers. The proposed all-van der Waals heterostructure provides a scalable platform for high-speed, energy-efficient, and reliable nonvolatile memory applications. The continued scaling of flash memory technologies faces challenges such as limited operation speed, poor data retention, and interface defects inherent to conventional three-dimensional architectures. Two-dimensional (2D) materials, with van der Waals interfaces and atomic-scale thickness, offer a promising pathway to overcome these limitations by enabling efficient charge modulation while minimizing surface defects. In this work, a nonvolatile 2D flash memory device is developed employing monolayer Janus MoSSe as the charge-trapping layer and hexagonal boron nitride (h-BN) as an ultrathin tunneling barrier. The intrinsic structural asymmetry of Janus MoSSe induces a strong vertical dipole moment, resulting in enhanced charge trapping, deeper energy barriers, and directional polarization compared with symmetric 2D materials. Consequently, the devices exhibit outstanding retention times exceeding 10 4  s, endurance beyond 10 4 program/erase cycles, and large memory window ratios (Δ V / V G,max of 50%–70% for 10 and 6 nm h-BN, respectively), with charge-trapping rates up to 8.96 × 10 14  cm −2  s −1 . In addition, Janus MoSSe-based devices show synaptic characteristics under electrical pulses and perform recognition simulations in artificial neural networks. These findings establish a design paradigm for 2D memory devices, enabling ultrathin, flexible, and energy-efficient nonvolatile memories.