Heterojunction construction on covalent organic frameworks for visible-light-driven H2O2 evolution in ambient air

Abstract

Photocatalytic H2O2 production by reducing O2 has drawn great interest, but most reactions were conducted in pure O2 which requires extra energy input. Here, TpPa-1 was facilely decorated by ZnIn2S4 nanosheets for H2O2 production in ambient air under visible light. Profiting from the hierarchical heterostructure, efficient visible-light absorption and O2 capture of ZnIn2S4/TpPa-1, an H2O2 yield of 516 μmol·L−1 was obtained with 2 h irradiation, which is 3.0 and 3.9 times those of blank TpPa-1 and ZnIn2S4, respectively. The intimate interface contact between ZnIn2S4 and TpPa-1 also contributes to the performance improvement. It is noted that the photocatalytic H2O2 formation over ZnIn2S4/TpPa-1 hybrids experienced an indirect reduction of O2 that ·O2- served as the key intermediate. Additionally, the reactions under different atmospheres and ethanol concentrations demonstrate that both O2 and ethanol play important roles in the efficient evolution of H2O2. This work could enlighten the heterostructure construction and (photo)catalytic H2O2 production based on covalent organic frameworks.