Construction of highly active WO_(3)/TpPa-1-COF S-scheme heterojunction toward photocatalytic H_(2)generation

The rapid charge recombination and low surface reaction kinetics are the two major constraints to the photocatalytic performance of covalent organic frameworks(COFs).To accelerate the charge separation behavior,TpPa-1-COF is decorated with WO_(3)Bvia an in-situ growth approach,and the resultant WO_(3)/TpPa-1-COF composites show significantly improved photocatalytic performance.Especially,when the WO_(3)loading arrives at 3 wt%,3%WO_(3)/TpPa-1-COF exhibits the maximum photocatalytic H_(2)evolution rate of 19.89 mmol g^(-1)h^(-1),which is approximately 4.8 times higher than that of pure TpPa-1-COF.The apparent quantum efficiency(AQE)of 3%WO_(3)/TpPa-1-COF at 420 nm is detected to be 12.4%.X-ray photoelectron spectroscopy(XPS)characterization confirms the formation of internal electric field between WO_(3)and TpPa-1-CF,which can drive the photogenerated charge carrier diffusion in S-scheme mode.As a result,WO_(3)/TpPa-1-COF composite possesses high charge separation efficiency and strong redox ability,which is further supported by the photoelectrochemical results,thus benefiting the photocatalysis process.This work provides a rational strategy to modify COFs in photocatalytic water splitting.