Ni²⁺/Co²⁺ doped Au-Fe₇S₈ nanoplatelets with exceptionally high oxygen evolution reaction activity

To overcome the limited potency of energy devices such as alkaline water electrolyzers, the construction of active materials with dramatically enhanced oxygen evolution reaction (OER) performance is of great importance. Herein we developed an ion diffusion-induced doping strategy that is capable of producing Ni²⁺/Co²⁺ doped two-dimensional (2D) Au-Fe₇S₈ nanoplatelets (NPLs) with exceptionally high OER activity outperforming the benchmark RuO₂ catalyst. The co-existence of Co and Ni in Au-Fe₇S₈ NPLs led to the lowest OER overpotential of 243 mV at 10 mA cm^-2 and fast kinetics with a Tafel slope of 43 mV dec^-1. Density functional theory (DFT) calculations demonstrated that Ni²⁺/Co²⁺ doping improves the binding of OOH species on the {001} surfaces of Au-Fe₇S₈ NPLs and lowers the Gibbs free energy of the OER process, which are beneficial to outstanding OER activity of the nanoplatelets.