Surface molecule induced effective light absorption and charge transfer for H2 production photocatalysis in a carbonized polymer dots-carbon nitride system

Current sunlight-powered H 2 production that employ carbonized polymer dots (CPDs)-graphitic carbon nitride (g-C 3 N 4 ) systems has made significant progress. However, we still have a limited understanding of the mechanism by which CPDs contribute to the phtocatalytic efficiency. Surface molecule 1,2,3,5-tetrahydro-5-oxo-imidazo[1,2- α ]pyridine-7-carboxylic acid (IPCA) has been verified to largely impact the photophysical properties of CPDs. Here, we report the design of g-C 3 N 4 , IPCA-g-C 3 N 4 and CPDs-g-C 3 N 4 catalysts to uncover the critical role of IPCA. The photocatalytic H 2 production rates of g-C 3 N 4 were improved by the hybridization with IPCA and CPDs (1172 ± 39; 2150 ± 92 vs. 828 ± 121 μmol g −1 h −1 , respectively). The DFT calculations further unraveled that electron transfer pathway in ICPA-CN@H 3 O + followed ICPA -> g-C 3 N 4 -> H 3 O + procedure. The results indicate that IPCA on CPDs is conducive to extending the light-responsive range, redistributing of photoinduced electron-hole pairs, increasing the electron density of g-C 3 N 4 , and thus improving H 2 generation rates.