Smart Yolk/Shell ZIF-67@POM Hybrids as Efficient Electrocatalysts for the Oxygen Evolution Reaction

The purpose of this research is to develop an effective and inexpensive oxygen evolution reaction (OER) electrocatalyst to achieve high-efficiency water decomposition. Herein, Keggin-type polyoxometalate (POM) nanoparticles coated with zeolitic imidazolate framework (ZIF-67) were successfully synthesized by facile methods. An efficient ZIF-67@POM catalyst with yolk/shell structure is reported. The POM nanomaterials are uniformly dispersed in the surface of ZIF-67. This unique yolk/shell structure with potential synergistic interaction between POM and ZIF-67 results in superior electrocatalytic activity in OER. When the current density is 10 mA cm–2, the overpotential is only 287 mV, and the Tafel slope is 58 mV per decade. Moreover, the as-prepared yolk/shell ZIF-67@POM catalysts exhibit excellent cycling stability, high surface area, abundant surface active sites, and high diffusion efficiency comparable to the traditional noble-metal-free OER electrocatalyst.