MoZn-based high entropy alloy catalysts enabled dual activation and stabilization in alkaline oxygen evolution.

Mei, Yunjie; Chen, Jinli; Wang, Qi; Guo, Yaqing; Liu, Hanwen; Shi, Wenhui; Lin, Cheng; Yuan, Yifei et al. · Sci Adv · 2024

basic_science · Level V

Where this comes from

Abstract

It remains a grand challenge to develop electrocatalysts with simultaneously high activity, long durability, and low cost for the oxygen evolution reaction (OER), originating from two competing reaction pathways and often trade-off performances. The adsorbed evolution mechanism (AEM) suffers from sluggish kinetics due to a linear scaling relationship, while the lattice oxygen mechanism (LOM) causes unstable structures due to lattice oxygen escape. We propose a MoZnFeCoNi high-entropy alloy (HEA) incorporating AEM-promoter Mo and LOM-active Zn to achieve dual activation and stabilization for efficient and durable OER. Density functional theory and chemical probe experiments confirmed dual-mechanism activation, with representative Co-Co<sup>†</sup>-Mo sites facilitating AEM and Zn-O<sup>†</sup>-Ni sites enhancing LOM, resulting in an ultralow OER overpotential (η<sub>10</sub> = 221 mV). The multielement interaction, high-entropy structure, and carbon network notably enhance structural stability for durable catalysis (>1500 hours at 100 mA cm<sup>-2</sup>). Our work offers a viable approach to concurrently enhance OER activity and stability by designing HEA catalysts to enable dual-mechanism synergy.