Bimetallic substrate induction synthesis of binder-free electrocatalysts for stable seawater oxidation at industrial current densities

Abstract

Oxygen evolution reaction (OER) is a bottleneck half-reaction of water splitting due to its sluggish kinetics involving four-electron transfer process. Developing a facile strategy for synthesis of low-cost and highly efficient OER catalysts is crucial but still very challenging. Herein, a bimetallic substrate induction (BSI) strategy to integrally construct supported metal catalysts (SMCs) as binder-free electrode in one step is proposed. As-used NiFe foam (NFF) not only plays the roles of the metal source and the reducing agent for in-situ growth of NiFeOOH supported Ru nanoparticles, but also guarantees the strong interaction between the SMCs and NiFe substrate. Consequently, the self-supported Ru/NiFeOOH/NFF electrode exhibits extraordinary OER performance in both alkaline salty water and seawater electrolytes. It can achieve the industrial current density of 500 mA cm−2 in 1 M KOH and 1 M KOH seawater at overpotentials of 285 and 330 mV, respectively, together with robust durability for over 400 h under current density of 100 mA cm−2. The combined theoretical and experimental investigations reveal that the in-situ formed metal-supported interaction accounts for both the optimal electronic states and the chemical stability. Furthermore, this BSI strategy can be applied in natural seawater for the scalable preparation of SMCs, demonstrating the universal applicability of BSI strategy.