Self-standing hollow porous Co/a-WOx nanowire with maximum Mott-Schottky effect for boosting alkaline hydrogen evolution reaction
Jianpo Chen, Jianping Zheng, Weidong He, Haikuan Liang, Yan Li, Hao Cui, Chengxin Wang
Abstract
The sufficient utilization of Mott—Schottky effect for boosting alkaline hydrogen evolution reaction (HER) depends upon scale minimizing of interface components and exposure maximizing of Mott—Schottky interface. Here, a self-standing porous tubular Mott—Schottky electrocatalyst is constructed by a self-template etching strategy, where amorphous WOx (a-WOx) nano-matrix connects Co nanoparticles. This novel “Janus” electrocatalyst maximizes the Mott—Schottky effect by not only providing a highly exposed micro interface, but also simultaneously accelerating the water dissociation and optimizing the hydrogen desorption process. Experimental findings and theoretical calculations reveal that Co/a-WOx Mott—Schottky heterointerface triggers the electron redistribution and a build-in electric field, which can not only optimize the adsorption energy of the reaction intermediates, but also facilitate the charge transfer. Thus, Co/a-WOx requires an overpotential of only 36.3 mV at 10 mA·cm−2 and shows a small Tafel slope of 53.9 mV·dec−1 as well as an excellent 200-h long-term stability. This work provides a novel design strategy for maximizing the Mott—Schottky effect on promoting alkaline HER.