Artificial Photosynthesis of H<sub>2</sub>O<sub>2</sub> by Synergistically Interplayed ZnIn<sub>2</sub>S<sub>4</sub> and K<sup>+</sup>-Incorporated Polymeric Carbon Nitride
Shiqi Zeng, Lina Li, Zhenchun Yang, Jiahao Cui, Kun Wang, Chun Hu, Yubao Zhao
Abstract
On-site production of H 2 O 2 from O 2 and H 2 O by way of artificial photosynthesis is highly desirable for facilitating the application of H 2 O 2 -based advanced oxidation processes. Achieving descent H 2 O 2 production efficiency is challenging, due to the severe recombination of the photoinduced charges and the sluggish kinetics of the water oxidation reaction. In this work, a heterojunction of exfoliated K + -doped polymeric carbon nitride (K-CN) and zinc indium sulfide (ZnIn 2 S 4, ZIS) is constructed; an interfacial electric field is induced, and partial charge transfer from ZIS to K-CN is verified via a spectroscopic technique. The spatial separation of the photoinduced charges is significantly enhanced, and a remarkable photocatalytic H 2 O 2 production from O 2 and H 2 O is thus achieved, e.g., 1729.9 μmol h –1 g –1 and apparent quantum yield of 2.43% under irradiation of 420 nm. Mechanistic investigations reveal the essential role of superoxide radical (O 2 · – ) in O 2 to H 2 O 2 conversion.