TiO2 modified g-C3N4 with enhanced photocatalytic CO2 reduction performance

Titanium dioxide (TiO2) modified g-C3N4 for composite photocatalysts were fabricated by using ball-milling and calcination. The physicochemical properties of as-obtained photocatalysts were characterized by XRD, XPS, SEM, TEM, UV–vis DRS, PL and Photocurrents. The results show that the heterostructure successfully formed between TiO2 and C3N4, and the heterostructure could effectively enhance the separation rate of the photogenerated electrons and holes. Also the positions of conduction band (CB) and valence band (VB) changed with improving the amount of TiO2 in the as-prepared photocatalysts. The photocatalytic activities of as-prepared photocatalysts were investigated by photoreduction of CO2, the results exhibit that the composite photocatalysts clearly improve the photoreduction of CO2 to CH4 and CO. The highest yields of CH4 and CO are of 72.2 and 56.2 μmol g−1 at an optimized modified amounts of TiO2 under 4 h irradiation of 8 W UV lamp, respectively. The strategy of TiO2 modified C3N4 could successfully obtain effective photocatalyst for CO2 conversion. [Display omitted] •TiO2 modified g-C3N4 composite photocatalysts were fabricated by using ball-milling method and calcination.•The positions of conduction band (CB) and valence band (VB) changed with improving the amount of TiO2 in the composite photocatalysts.•The composite photocatalysts clearly improve the photoreduction of CO2 to CH4 and CO.