Mo−Ni‐based Heterojunction with Fine‐customized d‐Band Centers for Hydrogen Production Coupled with Benzylamine Electrooxidation in Low Alkaline Medium

Abstract

AbstractBenzylamine electrooxidation reaction (BAOR) is a promising route to produce value‐added, easy‐separated benzonitrile, and effectively hoist H2 production. However, achieving excellent performance in low alkaline medium is a huge challenge. The performance is intimately correlated with effective coupling of HER and BAOR, which can be achieved by manipulating the d‐electron structure of catalyst to regulate the active species from water. Herein, we constructed a biphasic Mo0.8Ni0.2N−Ni3N heterojunction for enhanced bifunctional performance toward HER coupled with BAOR by customizing the d‐band centers. Experimental and theoretical calculations indicate that charge transfer in the heterojunction causes the upshift of the d‐band centers, which one side facilitates to decrease water activation energy and optimize H* adsorption on Mo0.8Ni0.2N for promoting HER activity, the other side favors to more easily produce and adsorb OH* from water for forming NiOOH on Ni3N and optimizing adsorption energy of benzylamine, thus catalyzing BAOR effectively. Accordingly, it shows an industrial current density of 220 mA cm−2 at 1.59 V and high Faradaic efficiencies (>99 %) for H2 production and converting benzylamine to benzonitrile in 0.1 M KOH/0.5 M Na2SO4. This work guides the design of excellent bifunctional electrocatalysts for the scalable production of green hydrogen and value‐added products.