Rational design of carbon-doped TiO2 modified g-C3N4 via in-situ heat treatment for drastically improved photocatalytic hydrogen with excellent photostability

Graphitic carbon nitride (g-C3N4) photocatalysts have attracted much attention towards harvesting solar energy for applications in energy and environment sectors. However, separation of electron-hole pairs is an intrinsic problem for the bulk g-C3N4. Here, we report the tiny amount of carbon doped TiO2 modified g-C3N4 (C-TiO2/gC(3)N(4)) with a narrow bandgap and prolonged lifetime of charge carriers. This heterojunction photocatalysts were successfully fabricated via a facile heat treatment under atmosphere. The enhanced separation of photogenerated charge carriers and narrow band gap confer superior photocatalytic activities with 5.728 mmol/g photogenerated hydrogen gas for 5 h and 52.395 mmol/g for 64 h in triethanolamine aqueous solution. The apparent quantum efficiency of C-TiO2/g-C3N4 is similar to 6.2% under 420 nm irradiation, which is about 2.4 times higher than the corresponding value 2.6% of pristine g-C3N4. This photocatalyst with excellent photocatalytic performance and photo-stability can work as a promising candidate to applicate in solar-to-fuel conversion and environmental remediation.