The potential of converting traditional biomass into low-cost HER catalysts has broad application prospects. In this paper, fungus is used as a carbon-based carrier. The bimetallic catalyst RuM-C (M = V, Mo, W, Zn, Cu) was synthesized under inert gas protection at high temperature. The order of electrocatalytic activity is RuV-C > RuZn-C > RuW-C > RuMo-C > Ru-C > RuCu-C > BF-C, which indicates that RuV-C exhibits excellent HER activity. Due to its irregular sheet structure, the specific surface area of the catalyst is increased. Impressively, it exhibits extremely high catalytic activity for HER in 1 M KOH due to favorable kinetics and excellent specific activity. Consequently, the prepared RuV-C exhibited excellent and stable HER activity compared Ru-C with a low overpotential of 65.78 mV at the current densities of 10 mA cm-2and Tafel slope of 45.26 mV dec-1. The potential only decreased by 88 mV after 24 h of continuous testing, which indicates that the catalyst has outstanding stability. This work will provide positive inspiration for the promotion of a new Ru-based biomass HER electrocatalyst.
The fabrication of cost-effective hydrogen evolution reaction (HER) catalyst is a critical demand for environment-friendly energy generation with the replacement of precious metal based materials. As a powerful substitute for such purpose, Keggin heteropoly acid (HPA) H3PW12O40 (PW12) was taken as a crucial precursor to form the P–W–Ni oxide nanocomposites via electrospinning method with subsequent calcination. The characterizations of scanning electron microscopy, high resolution transmission electron microscope, x-ray powder diffraction, thermogravimetric analysis, Fourier transform infrared, Raman spectroscopy, and electrochemical method illustrated that the obtained composites were constituted of tungsten oxide phosphate (W18P2O59), nickel tungstate (NiWO4), and tungsten oxide (WO3). The crystalline PW12Ni5O43.5(isogenous) obtained at molar proportion of PW12 to NiAc2 in 1:5 exhibited excellent HER properties with small Tafel slope of 57 mV/decade and low overpotential of −0.35 V. The crystalline PW12Ni5O43.5(isogenous) nanocomposite synthesized from PW12 as precursor holds more excellent HER electrocatalytic performance than that of sample fabricated from (NH4)10W12O41 and H3PO4 as precursors. This is due to the uniformity morphology of PW12Ni5O43.5/FTO (isogenous) and enhanced synergistic effect between oxide components resulted from the favoring electrospinning process with the introduction of PW12. In this paper, PW12Ni5O43.5/FTO (isogenous) ternary nanocomposite were prepared as a facile and simple process, which allows easy control, good reproducibility, and cost-effectiveness. And PW12Ni5O43.5/FTO (isogenous) have excellent HER electrocatalytic performance.
To address the current issues of high costs and underutilization of energy storage systems (ESSs) on the distribution grids, the distributed ESS (DESS) during idle time can be aggregated to provide shared energy storage services and voltage regulation services to gain additional revenue. To achieve this win-win situation for both shared energy storage operators (SESO) and users, a trading mechanism based on a master-slave game has been established in this paper. The SESO takes the lead, setting power and capacity prices, and the users make decisions on biddings for ESS capacity and charging/discharging strategies based on the SESO's pricing schemes, their own loading conditions, and photovoltaic output estimations. The SESO then clears the final transaction scheme based on users' biddings while considering the network fees, operation task allocations to various DESSs, the voltage regulation costs incurred by transactions and the benefits of DESS participating in voltage regulation to ensure the system's feasibility and the economy. Finally, the efficiency and scalability of the proposed mechanism and solution are demonstrated through multi-user, multi-DESS case studies.
The SiO2/WO3/NiWO4 composites modified carbon nanofibers (SiWNi-CNFs) were prepared by a facile electrospinning method with following carbonization process under nitrogen atmosphere. The as-obtained SiWNi-CNFs were characterized by transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray photoelectron spectra (XPS), X-ray powder diffraction (XRD), FT-IR spectroscopy and Raman spectroscopy. As revealed by the electrochemical measurement, the SiWNi-CNFs prepared with SiW12/NiAc2 molar ratio of 1:1 presented best hydrogen evolution activity with a small Tafel slope (48 mV dec−1) among all the as-prepared samples. Notably, the as-prepared catalysts exhibit a small onset potential (0.29 V vs. reversible hydrogen electrode), high current density and excellent stability. The experimental results pointed that the SiWNi-CNFs processes more efficient hydrogen evolution properties than that other contrast samples. This is due to the SiO2/WO3/NiWO4 composite modified on the surface of carbon nanofibers can generate numerous active sites from the synergistic effect of each component. At the same time, the intimate combination of ternary oxide and carbon nanofibers can accelerate the electron transfer, enhance the stability and hinder the aggregation of active components during the carbonization. Moreover, the net-like structure stacked by carbon nanofibers should render the exposure of active sites and facilitate the mass transport for the HER process.
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