熔盐电脱氧工艺制备纳米级(VNbTaZrHf)C高熵碳化物及其析氢反应的催化性能

Preparation of Nanoscale (VNbTaZrHf)C High-Entropy Carbides via Molten Salt Electro-deoxidation and Its Catalytic Performance of Hydrogen Evolution Reaction

摘要:

通过在1173 K的CaCl₂中对金属氧化物和石墨进行电脱氧，制备了具有面心立方结构的纳米级(VNbTaZrHf)C高熵碳化物（HEC）粉末。适当的温度条件有利于抑制HEC颗粒的原位烧结生长。在1 mol/L KOH溶液中进行了电化学性能测试，探索(VNbTaZrHf)C HEC的催化性能。通过极化曲线、Tafel斜率、电化学阻抗谱和双层电容值CV测试评估了(VNbTaZrHf)C HEC的催化析氢反应（HER）性能。结果表明，(VNbTaZrHf)C HEC的双层电容值为40.6 mF/cm²。双层电容值越大，表明电化学活性表面积越大。由于(VNbTaZrHf)C HEC的高熵效应和纳米级结构，它表现出优异的催化HER性能，并为通过熔盐电脱氧制备HECs提供了新方法。

Abstract:

The nanoscale (VNbTaZrHf)C high-entropy carbide (HEC) powders with face-centered cubic structure were prepared by electro-deoxidation of metal oxides and graphite in CaCl₂ at 1173 K. Appropriate temperature conditions are favorable for suppressing the in-situ sintering growth of HEC particles. Electrochemical performance tests were conducted in 1 mol/L KOH solution to investigate the catalytic performance of (VNbTaZrHf)C HEC. The catalytic performance of (VNbTaZrHf)C HEC for hydrogen evolution reaction (HER) was evaluated through polarization curves, Tafel slope, electrochemical impedance spectroscopy, and double-layer capacitance value cyclic voltammetry tests. Results show that the double-layer capacitance value of (VZrHfNbTa)C HEC is 40.6 mF/cm². The larger the double-layer capacitance value, the larger the electrochemically active surface area. Due to the high-entropy effect and nanoscale structure of (VNbTaZrHf)C HEC, it exhibits superior catalytic performance to HER. This research provides a novel method for the preparation of HECs via molten salt electro-deoxidation.