Synergetic effect of carbon self-doping and TiO2 deposition on boosting the visible-light photocatalytic hydrogen production efficiency of carbon nitride

Abstract

To improve the visible light utilization and photogenerated carriers separation, carbon self-doped carbon nitride (C-CN) supported TiO2 photocatalysts were synthesized via a designed two-step strategy. After carbon self-doping, the colloid TiO2 were in-situ deposited on C-CN surface and crystalized by calcination. Simultaneously, the bulk C-CN structure was thermally exfoliated to nanosheet morphology. This strategy ensured the saturated deposition of colloid TiO2 nanoparticles on C-CN nanosheets to form well-constructed heterostructure with sufficient interfacial contact. The as-prepared TiO2/C-CN (TCN) heterojunction photocatalysts showed enhanced visible light absorption capability, resulting in impressively high hydrogen production efficiency as 212.7 μmol h−1, which was 10.8 times higher than that of CN. The remarkably enhanced photocatalytic performance may be mainly ascribed to synergetic effect of carbon self-doping and TiO2 deposition on the improved visible light utilization and photogenerated carriers separation. The probable mechanism in such well-constructed heterojunction photocatalysts was proposed based on the structural analysis, electrical and photoelectrical properties, and photocatalytic process. The proposed strategy may be extended to the preparation of diverse heterojunction photocatalysts with excellent performance for solar energy conversion.