Na, O co-doping and cyano groups synergistically adjust the band structure of g-C3N4 for improving photocatalytic oxygen evolution

Tuning the electronic structure is fundamental to improve the optical character and redox ability of photocatalysts. Thus, in this article, g-C3N4 with sodium and oxygen co-doping and cyano groups (NOC-CN) was successfully synthesized by a brief one-step thermopolymerization. The results indicate that introduction of sodium and oxygen dopant and cyano groups bring a narrower band gap for NOC-CN, adjust the overall electronic structure of NOC-CN in the positive direction, and facilitate more efficient electron migration ability, which promoted NOC-CN achieving photocatalytic water splitting oxygen evolution rate of 1.26 mmolh−1g−1 without the assistance of any co-catalyst. Furthermore, DFT calculation and related experimental results was also combined to confirm the chemical structure of NOC-CN. Obviously, this paper provides a feasible tactic to inflect the electronic construction of g-C3N4, improving its oxidizing ability.