Unraveling the Impact of Iron Incorporation Toward Efficient Oxygen Evolution Reaction of Nickel Tungstate

Abstract

To advance present research on electrochemical water splitting, it would be ideal to develop effective and long-lasting catalysts for the oxygen evolution process (OER). Herein, a novel mixed nickel-iron tungstate (FexNiyWO4) was synthesized by incorporating Fe into nickel tungstate using a straightforward hydrothermal approach. It was discovered that the introduction of Fe can reduce the crystallinity of NiWO4 and the obtained FexNiyWO4 catalyst is more favorable when electrochemical reconstitution occurs to generate the active species Ni(Fe)OOH. Consequently, the FexNiyWO4 shows dramatically boosted electro-catalyst performance, affording an overpotential of 262 mV at 10 mA cm-2 with a Tafel slope of 43.83 mV dec-1. More impressively, at a current density of 50 mA cm-2 after 50 hours, this catalyst displays excellent stability with barely any potential attenuation. This work offers a fresh viewpoint on the specific function of Fe on electrocatalytic OER of mixed-metal tungstate.

Keywords: Fe effect, Nickel-based tungstate, decrease crystallinity, reconstruction, OER activity