Enhanced CO evolution for photocatalytic conversion of CO₂ by H₂O over Ca modified Ga₂O₃

Artificial photosynthesis is a desirable critical technology for the conversion of CO₂ and H₂O, which are abundant raw materials, into fuels and chemical feedstocks. Similar to plant photosynthesis, artificial photosynthesis can produce CO, CH₃OH, CH₄, and preferably higher hydrocarbons from CO₂ using H₂O as an electron donor and solar light. At present, only insufficient amounts of CO₂-reduction products such as CO, CH₃OH, and CH₄ have been obtained using such a photocatalytic and photoelectrochemical conversion process. Here, we demonstrate that photocatalytic CO₂ conversion with a Ag@Cr-decorated mixture of CaGa₄O₇-loaded Ga₂O₃ and the CaO photocatalyst leads to a satisfactory CO formation rate (>835 µmol h^-1) and excellent selectivity toward CO evolution (95%), with O₂ as the stoichiometric oxidation product of H₂O. Our photocatalytic system can convert CO₂ gas into CO at >1% CO₂ conversion (>11531 ppm CO) at ambient temperatures and pressures.