Enhanced photocatalytic performance for hydrogen production and carbon dioxide reduction by a mesoporous single-crystal-like TiO2 composite catalyst

Photocatalytic water splitting is a promising technology for hydrogen fuel production and compares favorably with thermochemical and photobiological water-splitting techniques. Photocatalysts can also accelerate the photochemical conversion of carbon dioxide under solar irradiation into the fuel gas CH4, which is one sustainable solution to address energy needs and climate change. The present study separately evaluated photocatalyzed hydrogen production and carbon dioxide reduction under simulated solar radiation in the presence of a NaH2PO2-modified TiO2/Bi2S3 photocatalyst prepared by a green hydrothermal and filtration method. The addition of the surfactant NaH2PO2 is favorable to the formation of the core–shell catalyst and enhances the transfer and separation of the photogenerated charges. The study findings show that the TiO2 particles were homogenously coated with Bi2S3 film and finely dispersed due to the action of the NaH2PO2, thus enhancing the photocatalytic activity and stability of the composite samples. This improved H2 production of 40.1 mmol g−1 h−1, which is the highest recorded figure for such, and the highest CO2 photoreduction to CH4 of 67.1 µmol g−1 h−1, which is the highest recorded figure, is almost double the highest photocatalytic CH4 production figure reported in the literature at the time this study was conducted.Graphical abstractThe addition of NaH2PO2 enhanced the photocatalytic performance of TiO2@Bi2S3 to a H2 production of 40.1 mmol g−1 h−1, while a CH4 of 67.1 μmol g−1 h−1 reduction from CO2, which are both the highest productions as far as we know.