Enhancing electrocatalytic activity of bifunctional Ni3Se2 for overall water splitting through etching-induced surface nanostructuring

Electrocatalysts for oxygen evolution reaction (OER) has been at the center of attention for water splitting reactions. In this article we have presented a methodology to significantly improve the OER catalytic efficiency of electrodeposited Ni3Se2 films. Specifically, the pristine Ni3Se2 on surface nanostructuring induced through electrochemical etching shows a remarkable decrease of overpotential (@10 mA cm−2) to 190 mV, making it as one of the best OER elecrocatalyst known till date. Through detailed structural and morphological characterization of the catalyst film, we have learnt that such enhancement is possibly caused by the increased surface roughness factor and electrochemically active surface area of the etched film. The morphology of the film also changed from smooth to rough on etching further supporting the enhanced catalytic activity. Detailed characterization also revealed that the composition of the film was unaltered on etching. Ni3Se2 film was also active for HER in alkaline medium making this a bifunctional catalyst capable of full water splitting in alkaline electrolyte with a cell voltage of 1.65 V.