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

Benzylamine electrooxidation reaction (BAOR) is a promising route to produce value-added, easy-separated benzonitrile, and effectively hoist H-2 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 H-2 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.