Built‐in Electric Field in Yolk Shell CuO‐Co3O4@Co3O4 with Modulated Interfacial Charge to Facilitate Hydrogen Production from Ammonia Borane Methanolysis Under Visible Light.

Developing highly efficient and low‐cost catalysts is an endless challenge in the field of producing H2 from ammonia borane (AB). Herein, the manufacture of yolk‐shell CuO‐Co3O4@Co3O4 nanocomposites are reported by using Cu2O@CuO as a template, in which CuO‐Co3O4 is encapsulated into the Co3O4 hollow nanocubes. Due to the unique morphology and built‐in electric field (BIEF) induced by the CuO‐Co3O4 interface, the CuO‐Co3O4@Co3O4 nanocomposites display remarkable catalytic activity in AB methanolysis. The turnover frequency (TOF) is 24.8 min‐1 in the absence of light and significantly increases to 33.9 min‐1 when exposed to visible light. The experimental and theoretical calculations demonstrate that charge migration from CuO to Co3O4 results in the formation of dual active sites (Cu and Co sites) in charge of adsorption and activation of CH3OH and AB, respectively. Visible light‐induced acceleration is likely caused by type‐II heterojunction, which allows a large number of photogenerated electrons to accumulate in the CuO conduction band. This effectively activates the adsorbed CH3OH on the Cu site, rendering it easier to break the O−H bond. A plausible reaction mechanism involved the activation of the O−H bond of CH3OH, as the RDS is proposed according to the FT‐IR and kinetic isotope effect (KIE) experiments. This work offers an avenue to rationally design high‐performance yolk‐shell catalyst for rapid hydrogen production from AB methanolysis reaction under visible light. [ABSTRACT FROM AUTHOR]