High-efficient charge separation driven directionally by pyridine rings grafted on carbon nitride edge for boosting photocatalytic hydrogen evolution

Intramolecular doping of conjugated nitrogen heterocycles in carbon nitride (CN) has been used to promote charge separation, but it also causes recombination of photogenerated electrons and holes due to their in-plane non-directional transfer. Herein, it achieves the dual regulation of adjusting electron hybridization structure and electron directional transfer from centre to edge of CN by grafting pyridine rings on the edge of CN framework, which effectively drives separation and avoids recombination of photogenerated carriers in plane. The photocatalytic HER rate of up to 6317.5 μmol g−1 h−1 is obtained over the optimum 2AP-CN-15 sample, which has 3.9-fold increase over primal CN. Moreover, the apparent quantum efficiency of HER reaches up to 20.1 % at 420 nm. This work performs an essential insight into edge decoration effect of pyridine rings on CN, which affords a new guidance for the modification of CN-like materials with conjugated nitrogen heterocycles for high-efficiency photocatalytic application.