Ionic liquid assisted construction of B and P double doped porous g-C3N4 nanosheets with significantly enhanced photocatalytic H2 production

N-type B and P double doped porous g-C3N4 (CN–B–P) nanosheets is successfully prepared by using melamine and cyanuric acid as precursors, [Emin]BF4 and [Bmim]PF6 as B and P sources. The reason for obtaining a porous structure is that the raw material is decomposed to produce gas molecular etching materials such as CO2 and NH3 in the process of pyrosynthesis. The formed porous structure provides largest specific surface area (BET), which reach 137.49 m2g−1. A largest BET and porous morphology are conducive to providing more reactive sites. It short the electron transfer path and accelerate the electron transfer efficiency. Under the influence of B and P doping and porous structure, the H2 production of CN–45B–45P reach 9443.38 ​μmol/g/h, which is 12.34 times more than bulk carbon nitride CN (765.17 ​μmol/g/h), and is better than best sample (N–CN–45B–45P) without platinum as a cocatalyst (1187.34 ​μmol/g/h). In addition, the cyclic and continuous hydrogen production test results shows that the sample has excellent stability and durability.