Interfacial Electronic Modulation of Multishelled CoP Hollow Spheres via Surface Reconstruction for High-Efficient Hydrogen Evolution Reaction

The development of an efficient electrocatalyst for the hydrogen evolution reaction (HER) in alkaline media is of vital importance to water electrolysis. Herein, a facile surface reconstruction strategy of microwave radiation oxidation is reported to fabricate cobalt phosphide (CoP) multishelled hollow spheres with an amorphous cobalt oxide (CoOx) species coating layer (denoted as CoP@CoOx). The synergistic effect between multishelled hollow-structured CoP and amorphous CoOx can trigger strong electronic modulation on the heterointerface, leading to the increased electrochemical active surface area, the improved charge transfer, and the modification of the electronic structure. As a result, the significant improvements in the catalytic activity, long-term stability, and efficiency are achieved compared with pristine CoP. Especially, the CoP@CoOx composite by microwave radiation oxidation for 6 min on nickel foam (NF) displays significantly enhanced HER activity with a low overpotential of 35 mV at a current density of 10 mA cm(-2) and, even more remarkably, of 109 mV at ultrahigh current density of 100 mA cm( -2). The concept of interfacial electronic modulation by surface reconstruction can offer a unique approach for the rational design of hydrogen evolution catalysts and beyond.