Regulated effect of organic small molecular doped in carbon nitride skeleton for boosting photocatalytic hydrogen evolution

Organic small molecules doping in polymer carbon nitride (PCN) skeleton can dramatically improve photocatalytic performance owing to its effective regulation effect on molecular and electronic structure. Here, a new PCN-based photocatalyst is obtained via polymerization of urea with 1-benzyl-3-phenylthiourea (BPT). The doping effect of BPT in PCN skeleton directly adjusts the hybridization states and delocalization of molecular orbitals, so that the visible light harvest ability, adsorption capacity, charge separation efficiency and transfer kinetics are improved significantly. Consequently, the photocatalytic hydrogen evolution reaction (HER) rate reaches to 125.0 μmol h⁻¹ over the optimal PCN-BPT₁₅ photocatalyst, which is as 13.9 times as PCN (9.0 μmol h⁻¹). Noteworthily, a high apparent quantum efficiency (AQE) of 24.2% is achieved at 420 nm for photocatalytic HER. This work enriches the functionalized investigations of PCN-like photocatalysts by insight into regulated effect of organic small molecules in the skeleton for photocatalytic applications.