A function-switchable metal-free photocatalyst for efficient and selective production of hydrogen and hydrogen peroxide
Photocatalytic water splitting to produce hydrogen and hydrogen peroxide are the core issue of photocatalysis. Thought they are all water-based reactions, it’s extremely troublesome to conduct the two processes on one catalyst. Herein, a function-switchable metal-free catalyst was design and synthesized through the polycondensation of procyanidin and 4-methoxybenzaldehyde. Impressively, the catalyst developed here not only was expected to split water to produce hydrogen by four-electron reaction process in air free, but also to generate hydrogen peroxide by preferentially reducing oxygen with two-electron pathway in air. The production rates of hydrogen and hydrogen peroxide reach 252.02 and 1385.42 μmol h-1g-1, respectively. Through in-situ transient photovoltage tests and kinetic analysis, a clear and fundamental understanding on the highly efficient and switchable functions was acquired over this photocatalyst. This study highlights a unique behavior, and provides an insight into the design of function-switch catalyst and the regulation of catalytic reactions.