Effect of phosphorus doping on electronic structure and photocatalytic performance of g-C3N4: Insights from hybrid density functional calculation

Graphitic carbon nitride (g-C3N4), as a promising visible-light photocatalyst, has wide applications on water splitting, pollutants decomposition and CO2 reduction. Herein, we investigated the electronic and optical property of pure and P doped g-C3N4 using Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional method. The valuable features such as, the band structure, density of states, band decomposed charged density and optical absorption were computed to explore the role of phosphorus substitute N2 and C1 sites of g-C3N4.The results indicated that pure g-C3N4 has an indirect band gap of about 2.73 eV, which is in good agreement with the experimental value. By doping P into N2 and C1 sites of g-C3N4, the band gap reduces to 2.03 and 2.22 eV, respectively. Optical absorption intensity of g-C3N4 had a greatly enhancement in the visible region by doping P. Though narrowing the energy band of g-C3N4 by doping P, conduction band and valance band edge of g-C3N4 doping system still had enough potential to split water. Therefore, phosphorus doped g-C3N4 is effective strategy to improve visible light response photocatalytic performance of g-C3N4.