Template‐Free Synthesis of Zinc Cobalt Oxides/Phosphides (Co2P/CoO/ZnCo2O4) Hollow Sub‐Micron Boxes as Hydrogen Evolution Reaction Catalysts

Abstract

AbstractIn this work, we report the template‐free synthesis of zinc cobalt oxides/phosphides (Co2P/CoO/ZnCo2O4) hollow sub‐micron boxes as electrocatalysts for HER (hydrogen evolution reaction). The synthesis of such sub‐micron box starts with the preparation of the hollow oxide sub‐micron box and is followed by a phosphorization process. It is proven that the selective etching induces by cation exchange (Zn2+ and Co2+) was the key to the formation of the hollow structure. The analysis of chemical states and electrochemical activity further reveals Zn enhanced the intrinsic activity of catalysts by increasing the electron density of Co in final products. The optimized ZnCo‐OP hollow sub‐micron box exhibits good HER activity with overpotentials of 112 mV at 10 mA/cm2 and 197 mV at 250 mA/cm2.