Room-temperature photosynthesis of propane from CO(2) with Cu single atoms on vacancy-rich TiO(2)

Photochemical conversion of CO(2) into high-value C(2+) products is difficult to achieve due to the energetic and mechanistic challenges in forming multiple C-C bonds. Herein, an efficient photocatalyst for the conversion of CO(2) into C(3)H(8) is prepared by implanting Cu single atoms on Ti(0.91)O(2) atomically-thin single layers. Cu single atoms promote the formation of neighbouring oxygen vacancies (V(O)s) in Ti(0.91)O(2) matrix. These oxygen vacancies modulate the electronic coupling interaction between Cu atoms and adjacent Ti atoms to form a unique Cu-Ti-V(O) unit in Ti(0.91)O(2) matrix. A high electron-based selectivity of 64.8% for C(3)H(8) (product-based selectivity of 32.4%), and 86.2% for total C(2+) hydrocarbons (product-based selectivity of 50.2%) are achieved. Theoretical calculations suggest that Cu-Ti-V(O) unit may stabilize the key *CHOCO and *CH(2)OCOCO intermediates and reduce their energy levels, tuning both C(1)-C(1) and C(1)-C(2) couplings into thermodynamically-favourable exothermal processes. Tandem catalysis mechanism and potential reaction pathway are tentatively proposed for C(3)H(8) formation, involving an overall (20e(−) – 20H(+)) reduction and coupling of three CO(2) molecules at room temperature.