Synergetic Role of Thermal Catalysis and Photocatalysis in CO 2 Reduction on Cu 2 /MoS 2 .

Effective activation of CO 2 is a primarily challenging issue in CO 2 reduction to value-added hydrocarbon chemicals, due to the large energy gap between the highest-occupied and lowest-unoccupied molecular orbitals (HOMO-LUMO). Here, we employ state-of-the-art first-principles calculations to explore the synergetic role of thermal catalysis and photocatalysis in CO 2 reduction, on typical single-atom scale catalyst, i.e., Cu 2 magic cluster on a semiconducting two-dimensional MoS 2 substrate. It is identified that only about 1% of the hot electrons excited from the MoS 2 substrate by at least 6.3 eV photons may be trapped by the inert CO 2 molecule at the expense of 400 fs. Moreover, the physisorption-to-chemisorption transition of CO 2 can be observed within 500 fs upon overcoming an about 0.05 eV energy barrier. Contrastingly, upon chemisorption, the activated CO 2 δ- species may trap about 7% of the hot electron excited from the MoS 2 substrate by about 2.5 eV visible photons, with a cost of 140 fs.