Dual-Defect Engineering of Mo-Doped NiFe-LDH Nanosheets for Enhanced Alkaline Oxygen Evolution

Defect engineering is considered to be a crucial strategy for efficiently designing catalysts. It has been demonstrated that the introduction of multiple defects significantly contributes to the optimization of the internal electronic structure of the catalyst, but there is a lack of in-depth understanding of the synergistic mechanism of multiple defects and the intrinsic behavior of the electrodes under defect modification. Herein, in this paper, NiFe-DMo nanosheets decorated by dual defects (including Mo dopants and Ni vacancies) were prepared by the electrodeposition method, which increased the density of active sites and altered the electronic structure of the catalysts through the dynamic dissolution and polymerization process of Mo. Electrochemical tests showed that the dual defects of Mo enhanced the OER activity and stability of the catalyst with an overpotential of 211 mV at 10 mA cm–2. Density functional theory (DFT) calculations further revealed that the dual defects of Mo optimized the adsorption energy of the OER intermediates. In addition, the effect of the leaching of inactive ions (MoO4–2) on the catalyst performance was investigated. Results found that the leaching of these ions promoted the reconstruction of the precatalyst to the active phase and revealed the Mo dissolution and readsorption mechanisms. This study provides ideas and theoretical basis for the design of efficient and stable Mo-based OER catalysts.