In-situ interfacial engineering of Co(OH)2/Fe7Se8 nanosheets to boost electrocatalytic water splitting

作者：Gong, Cheng; Zhao, Lei^*; Li, Dongming; He, Xuan; Chen, Hui; Du, Xing; Wang, Daheng; Fang, Wei; Zeng, Xianghui; Li, Weixin^*

来源：Chemical Engineering Journal, 2023, 466: 143124.

DOI：10.1016/j.cej.2023.143124

• In-situ selenization
• Interfacial engineering
• Heterostructure
• Electrocatalytic water splitting

Rational design of bi-functional catalysts with desirable activity and stability remains a challenge for overall water splitting. Herein, two-dimensional Co(OH)2/Fe7Se8 nanosheets are prepared via self-transformation and insitu selective selenization to construct rich heterogeneous interfaces. The in-situ interfaces induced by Fe7Se8 assist to regulate electronic structure of Co(OH)2/Fe7Se8 heterostructure. The incorporation of Fe species along with selective selenization offer strong interfacial coupling effect between Co(OH)2 and Fe7Se8. The in-situ formed interfaces contribute to optimized d-band center, lower energy barrier of intermediates and higher desorption capability of intermediates. Hence, the Co(OH)2/Fe7Se8 nanosheets exhibit superb electrocatalytic activity for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), requiring overpotentials of 183 and 278 mV at 10 mA cm-2 in 1.0 M KOH solution, respectively. In addition, the Co(OH)2/Fe7Se8 electrode requires only 1.62 V at 10 mA cm-2 in a two-electrode assembled electrolyzer, suggesting the promising application as overall water splitting electrocatalysts.