Surface in situ modulation of carbon nanotube-supported Fe–Ni compounds via electrochemical reduction to enhance the catalytic performance for the oxygen evolution reaction

Abstract

Exploring efficient strategies to enhance the catalytic performance for the oxygen evolution reaction (OER) is crucial for the rapid development of green hydrogen production based on water electrolysis. Here, a simple and extensible in situ electrochemical reduction method is proposed to improve the OER catalytic performance. A carbon nanotube-supported iron–nickel organometallic compound (Fe–Ni@CNT) and the corresponding R-Fe–Ni@CNT with further electrochemical reduction modulation serve as the pre-catalysts to obtain O–Fe–Ni@CNT and RO–Fe–Ni@CNT catalysts during the OER process, respectively. The characterization results show that the electrochemical reduction modulation can adjust the redox properties of the active species and the in situ transformation process to induce the formation of a greater abundance of Ni³⁺ (efficient OER active sites). Hence, the RO–Fe–Ni@CNT catalyst displays significantly enhanced OER catalytic activity and stability compared to the O–Fe–Ni@CNT catalyst. This work reveals the unique role of electrochemical reduction modulation in OER catalytic performance, providing more opportunities for the design of efficient catalysts.