Cathode electrochemically reconstructed V-doped CoO nanosheets for enhanced alkaline hydrogen evolution reaction

Abstract

• The crystalline V-doped CoO nanosheets were obtained by cathode electrochemical reconstruction of amorphous VCoO. • The crystallineV-doped CoO exhibited better HER active than amorphous VCoO. • Nanosheets structure could provide abundant active sites. • Vanadium doping effectively increased the intrinsic activity of CoO (1 1 1) and the number of active sites. • The V-doped CoO nanosheets display superb performance for HER at high potential. In the search for nonprecious metal catalysts to achieving active industrial hydrogen evolution reaction (HER), transition metal oxides (TMOs) have been proposed as promising candidates. In various synthetic methods for preparation of TMO electrocatalysts, electrochemical reconstruction, as one of the most efficient and controlled way, attracts much attentions. However, most of reported electrochemical reconstruction is usually carried out on the surface of anode via electrochemical oxidation reaction, and the investigations of cathode electrochemical reconstruction are rarely reported. Here, V-doped CoO nanosheets (V-CoO) are successfully prepared via cathode electrochemical reconstruction of amorphous VCoO. The reconstruction process and principle are studied in detail. Compared with the previous oxides, the obtained V-CoO possesses the promoted HER performance with overpotential of 280 mV at − 100 mA cm −2 and superior durability at − 1.07 V vs. RHE for 20 h. DFT calculations further reveals that vanadium doping effectively improves the intrinsic activity of oxides and HER active sites located at Co side of V-CoO (1 1 1) facet is the favorable H* adsorption site of reconstructed oxides. This work highlights the importance of electrochemical reconstruction on cathode to improve the HER activity of TMOs.