Carbon Nitride Polymer Sensitization and Nitrogen Doping of SrTiO3/TiO2 Nanotube Heterostructure toward High Visible Light Photocatalytic Performance

Construction of versatile multijunctions with visible light response, effective charges transport and separation, suitable band positions, and good stability is highly expected for the photocatalytic VOCs degradation. Herein, one-dimensional titania nanotube supported SrTiO3 heterostructure (STO/TN) was developed by a hydrothermal process and then simultaneously sensitized with carbon nitride polymer (CN) and doped with nitrogen (CN-STO/TN) for phofocatalytic mineralization of toluene. CN-STO/TN simultaneously exhibits the following advantages: (1) the nanotube structure enhances light-harvesting, enables effective charges transport and separation, retains sufficient energy of the charges, facilitates the pollutant species transport and reactants enrichment by the confinement effect; (2) synergistic effect of CN sensitization and N-doping extends the light response to the visible light region; (3) multichannel charges separation and transport among the multijunctions promote the photogenerated carriers separation. These beneficial factors lead to the remarkably higher visible light photocatalytic performance of CN-STO/TN in comparison with the component photocatalysts, 27 times that of TN, 13.5 times that of STO, and 4.9 times that of CN, respectively. These results demonstrate that the combination of morphology tailoring and energy band alignment manipulation is important in designing effective heterojunctions for photocatalytic applications.