A novel composite material based on hydroxylated g-C3N4 and oxygen-vacant TiO2 for improvement of photocatalytic performance

Aim to facilitate photogenerated carriers’s separation and transfer to enhance photocatalytic efficiency, a novel composite photocatalyst TCN70 was successfully prepared by combination of hydrothermal process with calcination using the hydroxylated g-C3N4 (CN-OH) and the oxygen-vacant TiO2 (Ov-TiO2) as precursors in this paper. The as-prepared composite photocatalyst exhibits much higher catalytic activity than that of the pristine CN-OH or Ov-TiO2. Application in degradation of phenol under visible light irradiation, a degradation rate of ca. 100% was obtained, much higher than that of 60% or of 32% in the case of individually using CN-OH or Ov-TiO2 as photocatalyst. Such remarkable improvement in photocatalytic performance is due to the synergy effect between CN-OH and Ov-TiO2, namely, a self-built electric field (E) resulting from the formation of a heterojunction at the interface between CN-OH and Ov-TiO2 facilitates photogenerated carriers’s separation and transfer and forms a “Z-scheme” photocatalysis mechanism involving in hydroxyl radicals generation.