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Photoreduction of CO₂ to hydrocarbons is a sustainable energy technology which not only mitigates emissions but also provides alternative fuels. However, one of the largest challenges is to increase the overall CO₂ photo-conversion efficiency when water is used as the reducing reagent. In this work, mesoporous silica supported Cu/TiO₂ nanocomposites were synthesized through a one-pot sol–gel method, and the photoreduction experiments were carried out in a continuous-flow reactor using CO₂ and water vapor as the reactants under the irradiation of a Xe lamp. The high surface area mesoporous silica substrate (>300m²/g) greatly enhanced CO₂ photoreduction, possibly due to improved TiO₂ dispersion and increased adsorption of CO₂ and H₂O on the catalyst. CO was found to be the primary product of CO₂ reduction for TiO₂–SiO₂ catalysts without Cu. The addition of Cu species, which was identified to …