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

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 2 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/cm(2). 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.