Unveiling the CoFe LDH generated by partial in situ conversion strategy: Synergistic effect of modified MXene and cationic vacancies for overall water splitting

Abstract

It remains a challenge to utilize non-precious metal electrocatalysts to increase intrinsic activity and observe more active sites. Herein, we propose a simple partial in situ transformation strategy to form a novel MOF@CoFe LDH heterostructure by Co-MOF template-directed fabrication using modified MXene as substrate, and introduce metal cation vacancy defects on the as-prepared LDH surface to further enhance the performance of the catalysts. Density-functional theory calculations show that the electron transfer rate of a material can be tuned by modulating the electron diffusion phenomenon, thereby lowering the energy barrier of the catalytic reaction. Consistent with the expected results, the catalysts also showed excellent electrochemical performance with HER and OER reaching current densities of 10 mA cm−2 with overpotentials of only 201 mV and 197 mV, and Faraday efficiencies (FE) close to 100 %. Meanwhile, a cell overpotential of only 1.56 V is required to effectively drive a current density of 10 mA cm−2 in the two-electrode system, and the superior long-term stability of the material reveals its potential for cost reduction in large-scale industrial applications.