Photocatalytic CO2 reduction to methanol over bismuth promoted BaTiO3 perovskite nanoparticle catalysts

Abstract

The photocatalytic reduction reactions of CO2 to methanol over bismuth-promoted BaTiO3 chemical photo-catalyst were reported for the first measurement time. Catalysts were prepared via single step deposition precipitation/solution combustion technique. Phases/morphology were characterised by powder X-ray diffraction (XRD)/scanning electron microscopy (SEM). Light absorption spectrum/bandgap energy (Eg) was calculated using ultraviolet–visible (UV–Vis) wavelength diffuse reflectance spectroscopy. The addition of Ba/Bi increased Eg. Comparing materials, synthesised by combusting, the latter showed a surface high basicity/water adsorption. Tests indicated the formation of alcohols. Bi-containing also demonstrated CO. No CH3OH was found for precipitated though. Activity resulted from the synergetic relationship effect between Bi/Ti, caused by the charge transfer mechanism between these component species, strong interaction phenomena and recombination. All were stable for a long temporal period. In the presence of the Ba or Bi metals over titania, the electrons (e–) from TiO2 form an e––hole pair separation, prolonging their decay lifetime. Ba/Bi-based TiO2 presented produced a CH3OH yield of 5.95 μmol gcat−1 h−1, higher compared to structured catalytic systems, described in specific literature reports. As opposed to hydrogen, CH3OH is a renewable storable liquid solar fuel, not only integrating carbon capture and utilisation (CCU), but also power-to-liquid.