Novel capture and photocatalytic conversion of CO2 into solar fuels by metals co-doped TiO2 deposited on PU under visible light

[Display omitted] •Ag and Cu co-doping formed Ti3+ and oxy-vacancies in the TiO2 lattice.•The formed Ti3+ and oxy-vacancies enhanced both the CO2 adsorption and conversion.•Ag and Cu co-doping also enhanced the separation of electron–hole pairs of the TiO2.•Ag@Cu-TiO2/PU converted CO2 into CH4 and CO even under visible light.•The optimal doping ratios of Ag/TiO2 and Cu/TiO2 were 2 and 4wt%, respectively. In this study, Ag and Cu co-doped TiO2 deposited on polyurethane (Ag@Cu-TiO2/PU) was synthesized for the conversion of CO2 into solar fuels under visible light. The synthesized Ag@Cu-TiO2/PU, which synergistically inherited all the advantages of both Ag and Cu doping, exhibited very high photocatalytic activity for the reduction of gaseous CO2 to produce CH4 and CO fuels. The dopants defects in the TiO2 lattice formed Ti3+ and oxygen vacancies in the lattice. The presence of Ti3+ and oxygen vacancies on the surface of the photocatalyst induced the formation of new adsorption sites to adsorb CO2. The Ag and Cu dopants also enhanced the separation of electron–hole pairs of the doped TiO2 photocatalysts. Therefore, the Ag@Cu- TiO2/PU photocatalysts generated electron–hole pairs, which could react with H2O and CO2 to produce the CO and CH4, even under visible light. 2Ag@4Cu-TiO2/PU, corresponding to the Ag/TiO2 and Cu/TiO2 ratios of 2 and 4wt%, respectively, exhibited the highest photocatalytic reduction of CO2. The yields of CH4 and CO produced from the photocatalytic reduction of CO2 by 2Ag@4Cu-TiO2/PU under visible light were 880 and 550 (μmol/g.cat), respectively.