Constructing high-activity Cobalt‐based Perovskite hybrid by a top-down phase evolution method for the direct seawater electrolysis anode

Abstract

The direct seawater electrolysis requires the robust oxygen evolution reaction (OER) catalysts with high activity and stability. Co-based perovskites with superior durability can be used as the promising OER catalysts for the direct seawater electrolysis, though their OER catalytic activity still needs to be improved. In this work, we propose a novel top-down phase evolution method to synthesize a Co-based perovskite hybrid (P/RP-SNCF) compositing the ABO3-type SrNb0.1Co0.7Fe0.2O3-δ (P-SNCF) and Ruddlesden-Popper Sr3NbCoO7-δ (RP-SNCF) perovskite by a facile annealing method. Compared with P-SNCF, the OER process of P/RP-SNCF prefers the lattice oxygen oxidation (LOM) pathway. The P/RP-SNCF hybrid shows significantly enhanced OER catalytic activity with the overpotential being as low as 335 mV at 10 mA cm-2. By the active surface reconstruction of P/RP-SNCF with electrochemical reduction, the optimized ER-P/RP-SNCF-5 shows the further improved OER activity. Furthermore, by using ER-P/RP-SNCF-5 as the anode for the direct seawater electrolysis, the electrolytic voltage reaches 1.57 V to yield a current density of 10 mA cm-2 and keeps stable for 100 h. The proposed strategy provides a new insight into the design of the high-performance perovskite hybrid for the direct seawater electrolysis.