Molten-salt assisted synthesis of Cu clusters modified TiO2 with oxygen vacancies for efficient photocatalytic reduction of CO2 to CO

The OVs and Cu NCs co-modified TiO2 samples exhibit superior performance for photocatalytic CO2 reduction to CO, reaching up to 40.3 μmol h−1 g−1. The excellent activity is attributed to the synergistic optimization of thermodynamics and kinetics by the Cu NCs and OVs, insuring the reaction pathway with a lower energy barrier. [Display omitted] •Molten-salt assistant synthesis of highly dispersed Cu NCs and stable OVs co-modified TiO2.•The as-prepared catalysts exhibit more competitive performance for photocatalytic CO2 reduction.•The presence of OVs may significantly promote the adsorption and activation of CO2.•The highly dispersed Cu NCs can promote the moderate dissociation of H2O.•The synergistic effect of Cu NCs and OVs optimizes the reaction pathway with a lower energy barrier. Design and preparation of efficient photocatalyst for CO2 reduction into fuels remains a serious challenge. Herein, the copper nanoclusters (Cu NCs) modified TiO2 with oxygen vacancies (OVs) samples (COCT) were obtained by a convenient molten-salt method. The liquid environment of isolate oxygen and the space confinement effect of molten-salt will lead to the generation of highly dispersed Cu NCs and stable OVs. This enables COCT to exhibit excellent photocatalytic CO2 reduction to CO performance with the highest CO generation rate reaching 40.3 μmol h−1 g−1, which is more competitive than most reported TiO2-based photocatalysts. The superior activity is ascribed to the synergistic optimization of the thermodynamics and kinetics of photocatalytic CO2 reduction to CO by Cu NCs and OVs, insuring the reaction pathway with a lower energy barrier. Our work may provide an easy and low-cost strategy for fabricating the highly dispersed cocatalyst together with surface defect to enhance artificial photosynthesis.