An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Abstract The nitrogenous nucleophile electrooxidation reaction (NOR) plays a vital role in the degradation and transformation of available nitrogen. Focusing on the NOR mediated by the β‐Ni(OH) 2 electrode, we decipher the transformation mechanism of the nitrogenous nucleophile. For the two‐step NOR, proton‐coupled electron transfer (PCET) is the bridge between electrocatalytic dehydrogenation from β‐Ni(OH) 2 to β‐Ni(OH)O, and the spontaneous nucleophile dehydrogenative oxidation reaction. This theory can give a good explanation for hydrazine and primary amine oxidation reactions, but is insufficient for the urea oxidation reaction (UOR). Through operando tracing of bond rupture and formation processes during the UOR, as well as theoretical calculations, we propose a possible UOR mechanism whereby intramolecular coupling of the N−N bond, accompanied by PCET, hydration and rearrangement processes, results in high performance and ca. 100 % N 2 selectivity. These discoveries clarify the evolution of nitrogenous molecules during the NOR, and they elucidate fundamental aspects of electrocatalysis involving nitrogen‐containing species.
This paper applies an adaptive method for regulating the proportional resonance (PR) controller for frequency and phase synchronization in 500 kW photovoltaic grid-connected inverter. First, this paper determines the mathematical model of the three-phase voltage source inverter (VSI) in the coordinate system, and presents an automatic way for parameter tuning in proposed PR controller framework. Second, the frequency variation is detected via minimizing the error signal using a frequency locked loop (FLL) mechanism which consists of a resonant adaptive filter and a perturbation-based extreme seeking (PES) method. Unlike the widely used proportional-integral (PI) controller and phase locked loop (PLL)-based frequency detection, the proposed adaptive PR (APR) controller shows high performance in items of steady-state error of current, frequency fluctuation tracking, phase shift error, and harmonic order compensation. At last, the simulation and experimental results demonstrate that the photovoltaic grid-connected inverter embedded with APR controller realizes the static-free tracking adjustment more quickly, and has stronger grid voltage anti-disturbance capability than the traditional PI-based voltage/current loop applications.
Gathering information from multi-perspective graphs is an essential issue for many applications especially for proteinligand binding affinity prediction. Most of traditional approaches obtained such information individually with low interpretability. In this paper, we harness the rich information from multi-perspective graphs with a general model, which abstractly represents protein-ligand complexes with better interpretability while achieving excellent predictive performance. In addition, we specially analyze the protein-ligand binding affinity problem, taking into account the heterogeneity of proteins and ligands. Experimental evaluations demonstrate the effectiveness of our data representation strategy on public datasets by fusing information from different perspectives.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Two-dimensional transition metal dichalcogenides (TMDs) have emerged as promising catalysts for the hydrogen evolution reaction (HER). However, they typically require the engineering of additional actives sites (e.g. vacancies and dopants) and/or the application of large external strains to launch the HER on their basal planes. Herein, we investigate the HER proceeding on the experimentally available single-layer PdX2 (X = S, Se), a novel group of pentagonal TMDs with high amounts of intrinsic X vacancies, through density functional theory computations. Our results indicate that single-layer PdX2 nanosheets with low concentrations of X vacancies exhibit favorable hydrogen adsorption free energy (ΔGH*) values, which is desirable for facilitating the HER. Their HER performance can be greatly enhanced using small external strains, during which ΔGH* can reach the optimal value of 0 eV. Moreover, a kinetic analysis based on the explicit water model and charge extrapolation scheme demonstrates that the HER occurs on the PdX2 nanosheets according to the Volmer-Tafel mechanism with low energy barriers. This work highlights the realization of high HER activity on TMDs featuring unique structural characteristics.
Electrocatalytic reduction of nitric oxide (NO) to ammonia (NH3 ) is a promising approach to NH3 synthesis. However, due to the lack of efficient electrocatalysts, the performance of electrocatalytic NO reduction reaction (NORR) is far from satisfactory. Herein, it is reported that an atomic copper-iron dual-site electrocatalyst bridged by an axial oxygen atom (OFeN6 Cu) is anchored on nitrogen-doped carbon (CuFe DS/NC) for NORR. The CuFe DS/NC can significantly enhance the electrocatalytic NH3 synthesis performance (Faraday efficiency, 90%; yield rate, 112.52 µmol cm-2 h-1 ) at -0.6 V versus RHE, which is dramatically higher than the corresponding Cu single-atom, Fe single-atom and all NORR single-atom catalysts in the literature so far. Moreover, an assembled proof-of-concept Zn-NO battery using CuFe DS/NC as the cathode outputs a power density of 2.30 mW cm-2 and an NH3 yield of 45.52 µg h-1 mgcat-1 . The theoretical calculation result indicates that bimetallic sites can promote electrocatalytic NORR by changing the rate-determining step and accelerating the protonation process. This work provides a flexible strategy for efficient sustainable NH3 synthesis.
Inorganic nanodendrites (NDs) have become a kind of advanced nanomaterials with broad application prospects because of their unique branched architecture. The structural characteristics of nanodendrites include highly branched morphology, abundant tips/edges and high-index crystal planes, and a high atomic utilization rate, which give them great potential for usage in the fields of electrocatalysis, sensing, and therapeutics. Therefore, the rational design and controlled synthesis of inorganic (especially noble metals) nanodendrites have attracted widespread attention nowadays. The development of synthesis strategies and characterization methodology provides unprecedented opportunities for the preparation of abundant nanodendrites with interesting crystallographic structures, morphologies, and application performances. In this review, we systematically summarize the formation mechanisms of noble metal nanodendrites reported in recent years, with a special focus on surfactant-mediated mechanisms. Some typical examples obtained by innovative synthetic methods are then highlighted and recent advances in the application of noble metal nanodendrites are carefully discussed. Finally, we conclude and present the prospects for the future development of nanodendrites. This review helps to deeply understand the synthesis and application of noble metal nanodendrites and may provide some inspiration to develop novel functional nanomaterials (especially electrocatalysts) with enhanced performance.
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