Co-prosperity of electrocatalytic activity and stability in high entropy spinel (Cr0.2Mn0.2Fe0.2Ni0.2Zn0.2)3O4 for the oxygen evolution reaction

A high entropy spinel oxide (Cr0.2Mn0.2Fe0.2Ni0.2Zn0.2)(3)O-4 is successfully synthesized via the solvothermal method, and its electrocatalytic properties for the oxygen evolution reaction (OER) are evaluated. The catalyst exhibits a low overpotential of 295 mV at 10 mA cm(-2), with a Tafel slope of 53.7 mV dec(-1) as well as promising long-term stability. The attractive performance can be attributed to the increased amount of high valence Ni3+ species, together with the improved adsorption ability of oxygenic species on the material surface, due to the contribution of the multi-metallic element doping strategy in high entropy spinel oxide. DFT calculation results prove that the covalency of the metal-oxygen bond is enhanced in the high entropy oxide, which is beneficial for the OER catalysis. The DOS profile analysis and different charge density mapping results further reveal the multi-metal synergistic contribution to the oxygen evolution reaction. This study provides a reference method for the design and development of high-entropy spinel oxides with excellent OER properties.