Construction of a novel heteropoly molybdophosphate/graphitized carbon nitride s-scheme heterostructure with enhanced photocatalytic H2O2 evolution activity

Abstract

The preparation of hydrogen peroxide using a photochemical energy conversion process is a promising green pathway. Herein, a series of graphite-phase carbon nitride/Polyoxometalate (CN-HMoP) composite photocatalysts were prepared by interlayer coordination and segregation strategies. During the synthesis process, the presence of –NH2 or H ions at the CN terminus makes it display a positive charge, which is capable of attracting HMoP with a polyanionic structure. Subsequently, the N atoms on the triazine ring preferentially coordinate with the Mo ions in HMoP to form Mo-N bonds, and the HMoP nanoparticles are able to be inserted layer by layer into the CN nanosheets by interlayer coordination to make the sheet exfoliation, which contributes to the enhancement of the transmission of photogenerated carriers. Notably, the establishment of the S-Scheme heterostructure facilitates the spatial separation of electron-hole pairs and maintains the strongest redox potential. More importantly, under solar/visible light irradiation, the H2O2 generation rate of CN-HMoP reached 137.1 μmol L-1h−1 and 113.1 μmol L-1h−1, which was 17.7 and 16.8 times higher than pristine CN. Therefore, this work can provide guidance for the synthesis of semiconductor photocatalysts for more efficient and green generation of H2O2.