Constructing quasi‐amorphous cobalt oxyhydroxide nanowires with synergy of anion and cation via ion exchange reconstruction for large-current–density oxygen generation

Abstract

Deep insight into the synergy between anion and cation aids in the maximization of catalytic activity and the rational exploitation of efficient oxygen-evolving catalysts. However, how to use ion exchange reconstruction to devise highly active and cost-efficient oxygen evolution reaction (OER) catalysts with anion and cation synergies for water electrolysis is rarely reported. Herein, the cobalt triphosphide (CoP3) nanowires are elaborately devised as a component-flexible precatalyst for directing an anodic reconfiguration with Ni cation exchange to construct a highly active and quasi‐amorphous cobalt oxyhydroxide (CoOOH) catalyst integrated with cation (Ni) substitution and oxyanion (PO43-) decoration (denoted by R-(Ni)CoP3). Interestingly, the structural evolution and the Ni cation exchange processes are captured through various in/ex situ techniques. The resultant R-(Ni)CoP3 nanowires display a splendid activity with low overpotentials of 406 and 420 mV to respectively deliver industrial grade current densities of 1000 and 1500 mA cm−2, and an outstanding stability over 300 h at a large current density of 500 mA cm−2, superior to most progressive cobalt-based OER materials and the benchmark IrO2. The combination of theoretical calculations with experimental studies demonstrate that the synergy of cation (Ni) substitution and oxyanion (PO43-) decoration can significantly modulate the electronic states of CoOOH and optimize the adsorption free energy of OER intermediates, thus immensely expediting the kinetics process and enhancing the charge transfer ability and the intrinsic OER activity. This research suggests ion-regulatory reconfiguration as a flexible and changeable strategy to construct various efficient and advanced catalysts for water electrolysis and beyond.