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Abstract:
Single-atom catalysts (SACs) have been extensively applied in CO2 reduction reactions (CO2RRs) due to their unique activity/selectivity and maximum atom efficiency. To form and stabilize SACs, introducing oxygen vacancies (VO) on metal oxide surfaces is a common strategy. However, there is a lack of studies on whether the single atoms (SAs) can be stably anchored on VO sites under real reaction conditions, which hinders the rational design of SACs for practical usage. Herein, we combine the first-principles calculations and an artificial intelligence approach to high-throughput screen the stability and activity of 3d, 4d, and 5d transition metal (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Os, Ir, Pt, Au, and Hg) SAs on eight defective metal oxide surfaces (ZnO(100), rutile TiO2(110), Co3O4(001), CoO(100), MnO(100), NiO(100), MgO(100), and ZrO2(111)) during the CO2RR. By evaluating the anchor energies of the 232 catalytic systems, 100 kinds of SACs are stably anchored by VO in vacuum, but only 28 of them remain stable with the adsorption of intermediates of the CO2RR (*COOH, *OCHO, *CO, *CHO, and *H). By subgroup discovery analysis, we elucidate that the stability is attributed to the electronegativity and number of outer electrons of SA, the d-band center of metal oxides, and the relative coordination number of the adsorbed species together. In the further analysis of the selectivity and activity for the CO2 conversion to CO, the VO-ZrO2(111)-supported Os SAC is predicted as most promising in electrocatalysis and Ru/VO-ZrO2(111) exhibits excellent catalytic performances in the reverse water-gas shift reaction.
