A recyclable molten-salt synthesis of B and K co-doped g-C3N4 for photocatalysis of overall water vapor splitting

Photocatalytic overall water splitting is one of the green and efficient energy technologies. Due to difficult release of O-2 from photocatalysts, the simultaneous generation of H-2 and O-2 is a critical challenge for water splitting. B and K co-doped g-C3N4 (B/K-g-C3N4) catalyst was synthesized by the recyclable molten-salt method in this study. Compared with the K doped and pristine g-C3N4 samples, B/K-g-C3N4 exhibited the highest photocatalytic activity for water vapor splitting under visible light illumination. The yield ratio of H-2 and O-2 reached approximately 2:1, and the corresponding rates were 1.18 and 0.58 mu mol/h after 24 h of illumination. The B/K-g-C3N4 sample demonstrated good photocatalytic stability after 9 cycles. Additionally, the co-doped g-C3N4 catalyst, obtained from the repeatedly recyclable salts, still exhibited equivalent photocatalytic activity. Based on the built structure model with g-C3N4, the HOMO and LUMO distributions were changed by B and K co-doping, leading to improved separation of photoinduced carriers. The photocatalytic mechanism for water splitting over g-C3N4 semiconductor was speculated.

Automated summary

The study synthesized B and K co-doped g-C3N4 catalyst, which exhibited high photocatalytic activity and good stability, indicating potential applications in overall water splitting.