Real Active Site Identification of Co/Co<sub>3</sub>O<sub>4</sub> Anchoring Ni-MOF Nanosheets with Fast OER Kinetics for Overall Water Splitting
Haoran Yin, Xinqiang Liu, Lixia Wang, Tayirjan Taylor Isimjan, Dandan Cai, Xiulin Yang
Abstract
Doping metals and constructing heterostructures are pivotal strategies to enhance the electrocatalytic activity of metal–organic frameworks (MOFs). Nevertheless, effectively designing MOF-based catalysts that incorporate both doping and multiphase interfaces poses a significant challenge. In this study, a one-step Co-doped and Co 3 O 4 -modified Ni-MOF catalyst (named Ni NDC-Co/CP) with a thickness of approximately 5.0 nm was synthesized by a solvothermal-assisted etching growth strategy. Studies indicate that the formation of the Co–O–Ni–O-Co bond in Ni NDC-Co/CP was found to facilitate charge density redistribution more effectively than the Co–O–Ni bimetallic synergistic effect in NiCo NDC/CP. The designating Ni NDC-Co/CP achieved superior oxygen evolution reaction (OER) activity (245 mV @ 10 mA cm –2 ) and robust long stability (100 h @ 100 mA cm –2 ) in 1.0 M KOH. Furthermore, the Ni NDC-Co/CP (+) ||Pt/C/CP (−) displays pregnant overall water splitting performance, achieving a current density of 10 mA cm –2 at an ultralow voltage of 1.52 V, which is significantly lower than that of commercial electrolyzer using Pt/C and IrO 2 electrode materials. In situ Raman spectroscopy elucidated the transformation of Ni NDC-Co to Ni(Co)OOH under an electric field. This study introduces a novel approach for the rational design of MOF-based OER electrocatalysts.