Enhanced photocatalytic performance for hydrogen production and carbon dioxide reduction by a mesoporous single-crystal-like TiO 2 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 CH 4 , 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 NaH 2 PO 2 -modified TiO 2 /Bi 2 S 3 photocatalyst prepared by a green hydrothermal and filtration method. The addition of the surfactant NaH 2 PO 2 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 TiO 2 particles were homogenously coated with Bi 2 S 3 film and finely dispersed due to the action of the NaH 2 PO 2 , thus enhancing the photocatalytic activity and stability of the composite samples. This improved H 2 production of 40.1 mmol g −1 h −1 , which is the highest recorded figure for such, and the highest CO 2 photoreduction to CH 4 of 67.1 µmol g −1 h −1 , which is the highest recorded figure, is almost double the highest photocatalytic CH 4 production figure reported in the literature at the time this study was conducted. Graphical abstract The addition of NaH 2 PO 2 enhanced the photocatalytic performance of TiO 2 @Bi 2 S 3 to a H 2 production of 40.1 mmol g −1 h −1 , while a CH 4 of 67.1 μmol g −1 h −1 reduction from CO 2 , which are both the highest productions as far as we know.