In situ growth of SeOx films on the surface of Ni–Fe–selenide nanosheets as highly active and stable electrocatalysts for the oxygen evolution reaction

Abstract

Reasonable design, extremely low-cost, high efficiency and high durability oxygen evolution reaction (OER) catalysts are essentially required to promote the practical large-scale applications of electrocatalytic water splitting for the efficient production of hydrogen. Herein, a rapid, facile, green and controllable electrochemical deposition method is reported for the growth of SeO_x films on the surface of Ni–Fe–selenide nanosheets (SeO_x/FeNi_xSe) through the hydrogen evolution reaction (HER) cycle process, which are used as highly active and stable electrocatalysts for the OER. The obtained SeO_x/FeNi_xSe heterojunction nanosheets have interconnected heterostructures, which play a vital role in boosting the catalytic performance by offering rich active sites and convenient pathways for rapid electron transport. Detailed spectroscopic and DFT investigations disclose that the strong electron interaction between FeNi_xSe and SeO_x could reduce the surface charge-transfer-resistance, and improve the electrocatalytic properties and the structural stability of the electrode. The optimized SeO_x/FeNi_xSe (CM7-FeNi_xSe) catalyst exhibits superior OER activities to the commercial Ir and most of the reported Ni-based selenide catalysts with a small overpotential of 285 mV to achieve a current density of 200 mA cm⁻² in 1.0 M KOH. This finding provides a new ultrathin oxide layer preparation strategy to boost the OER catalytic activity.