Synthesis of metal-free phosphorus doped graphitic carbon nitride-P25 (TiO2) composite: Characterization, cyclic voltammetry and photocatalytic hydrogen evolution

Herein, the improved visible-light photocatalytic activity towards efficient hydrogen generation using modified P25 (TiO2) has been demonstrated. The P25 has been modified with pure and Phosphorus doped graphitic carbon nitride (CN and PCN) successfully and well-characterized by several analytical techniques. The effect of Phosphorus doping in CN favours to tune the opto-electronic and textural properties. The optimized composite of CN–P25 and PCN–P25 shows nearly twenty-two-fold (920 μmol/g) and forty-fold (2531 μmol/g) enhancement in hydrogen production as compared to CN and PCN respectively and nearly ten-fold and twenty-five-fold enhancement in hydrogen production as compared to P25. This overwhelming enhancement in hydrogen production can be attributed to the lowering of the conduction band by 0.13 eV and small conduction band offset of 0.35 eV estimated by cyclic voltammetry, which provokes the electron-hole recombination and better charge transfer at the PCN–P25 interface. These results unlock great avenues to develop the low cost and metal-free photocatalyst by simply modifying P25 with PCN in the field of energy and clean environment. [Display omitted] •Metal free Phosphorus doped gC3N4–P25 (PCN–P25) composites were synthesized for enhanced photocatalytic hydrogen evolution.•Band gap and texture tuning of gC3N4 by phosphorus doping makes it more photocatalytically active in the visible spectrum.•The optimized 2.0PCN–P25 composite showed ~40-fold & 25-fold enhancement in hydrogen evolution activity than PCN and P25.•CV data confirms that the incorporation of P in CN lowers the CB by 0.13 eV, with a small CBO at the PCN–P25 interface.•The proposed mechanism using CV analysis highlights the efficient charge transfer with low recombination at the interface.