Realizing the bifunctional electrocatalysis via local charge rearrangement of α-CrOOH-modulated Co@CoMoOx for overall water splitting

Abstract

Rational design of highly active, durable and cost-efficient bifunctional catalysts for electrochemical water splitting is critical for aggressive reform of energy technologies. Herein, earth-abundant transition-metal (TM) oxide-(oxy)hydroxide (Co@CoMoOx-α-CrOOH) is synthesized as overall water splitting catalyst via a facile electrodeposition approach. Detailed X-ray absorption spectra (XAS) reveal that incorporation of α-CrOOH can implicitly modulate the local coordination environment and the electronic structure of Co/Mo/Cr cations, as well as their synergistic interaction that contributes to more rapid charge-transfer kinetics and enhanced catalytic activity. The precisely designed Co@CoMoOx-α-CrOOH/NF electrode displays prominent overall water-splitting efficiency that require a cell voltage only 1.57 V to achieve 10 mA cm−2 along with remarkable stability over 24 h in alkaline solution, which is comparable to a Pt/C/ NF || IrO2/NF water-splitting device at the state of the art. This work provides a sustainable strategy to design efficient and cost-effective TM oxide-based catalysts for water-splitting application.