Abstract
Significant improving g-C3N4's photocatalytic efficiency still remains a great challenge.In this work,we synthesized ultrathin and porous 2D g-C3N4 nanosheets with a controllable concentration of carbon vacancies and oxygen doping.Water vapor opens the heptazine units,introduces carbon vacancies,and acts as an oxygen source for oxygen doping under high temperatures.The synergistic effect of controllable carbon vacancies and oxygen doping can continuously regulate band structures and significantly improves the separation efficiency of photoexcited charges.As a result,the prepared g-C3N4 with vigoroso reduction potential exhibits a very high photocatalytic H2 evolution rate of 2.414 mmol g~(-1)h~(-1)under visible light and 7.414 mmol g~(-1)h~(-1)under ultraviolet-visible light,respectively,which outperforms the majority of the previously reported g-C3N4 with well-tuned band structure.This work offers a new design idea for highly active g-C3N4-based photocatalysts with a well-tuned band structure.
NSTL