Synergistic Enhancement Effect of Cobalt Partial Substitution and Ni/Fe Ratio Regulation on the Oxygen Evolution Performance of NiFe-LDH

This study systematically demonstrates the effects of Ni/Fe ratio regulation and partial Co substitution on the microstructure and electrocatalytic oxygen evolution performance of Ni x Fe-LDH materials. The synergistic regulation of multiple metals provides an effective approach for enhancing the OER activity of LDH based catalysts. In this work, we report a Co partially substituted Ni x Fe-LDH nanosheet, denoted as Co 1 Ni 4 Fe-LDH, which was synthesized via a simple coprecipitation method. With a Ni/Fe ratio of 5 to 1 and a Co substitution level of one fifth, the catalyst exhibits excellent OER activity in alkaline media, achieving an overpotential of 371 mV at a current density of 100 mA cm −2 and a Tafel slope of 78.16 mV dec −1 . Moreover, after a 60h stability test at a current density of 100 mA cm −2 , the overpotential decreases by 23 mV without obvious performance degradation, which can be ascribed to the Co doping induced optimization of electronic structure and lattice distortion effects that synergistically enhance the reaction kinetics and structural stability. As a typical model, Co 1 Ni 4 Fe-LDH demonstrates outstanding oxygen evolution catalytic capability and holds significant potential for the development of high efficiency non-noble metal electrocatalysts for water splitting.