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

Photocatalytic H2O2 production by reducing O-2 has drawn great interest, but most reactions were conducted in pure O-2 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 O-2 capture of ZnIn2S4/TpPa-1, an H2O2 yield of 516 mu mol center dot 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 O-2 that center dot O-2(-) served as the key intermediate. Additionally, the reactions under different atmospheres and ethanol concentrations demonstrate that both O-2 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.