Enhancing Oxygen Evolution Performance of Cobalt–Vanadium Nanocomposites by Ion Leaching

Co‐based catalysts have been widely used in oxygen evolution reaction (OER) because of their low price and excellent catalytic performance. Herein, strategies of ion leaching and surface reconstruction to form more catalytic active sites are proposed, and accordingly improving the intrinsic activity of OER catalyst. First, the Co‐metal–organic frameworks (MOFs)/Ni precursors are synthesized on Ni foam by hydrothermal method. Then, the second hydrothermal reaction is carried out in sodium metavanadate solution, and a highly active V‐doped Co‐MOFs/Ni OER catalyst with particle coating is obtained. The results show that V‐doped Co‐MOFs/Ni in 1 m KOH solution shows excellent performance, that is, low overpotential of 253 mV at 10 mA cm −2 , Tafel slope of 56 mV dec −1 , small charge transfer impedance, large electrochemically active area of 1.71 mF cm −2 , and good stability. Inductively coupled plasma‐atomic emission spectrometry measurements confirm that the V ions play a dominant role in leaching, while the Co ions negligibly contribute to the leaching. This work paves an alternative approach for advancing the synthesis of high‐efficiency nonprecious OER catalysts by such a facile green method.