Synergism between {111} and {100} Crystal Facets on\nCu<sub>2</sub>O for Boosted Photothermal Catalysis

Cu<sub>2</sub>O with different morphologies (Cu<sub>2</sub>O–C\n(Cube), Cu<sub>2</sub>O–CB (Cuboctahedra), and Cu<sub>2</sub>O–O (Octahedra)) was synthesized to investigate the effect\nof crystal planes for the photothermal catalytic oxidation of toluene.\nIt was found that the order of catalytic activity was as follows:\nCu<sub>2</sub>O–CB > Cu<sub>2</sub>O–O > Cu<sub>2</sub>O–C. The H<sub>2</sub>-TPR and XPS results showed that\nthe\n{111} facets were more susceptible to oxidation, and the oxidized\nstructure was more difficult to reduce. The combination of {100} and\n{111} on Cu<sub>2</sub>O–CB showed a synergistic effect between\nthe oxidation and reduction cycle. Moreover, the {100} facets showed\nhigh electron–hole separation efficiency, which could promote\n the formation of •O<sub>2</sub><sup>–</sup> species. <i>In-situ</i> DRIFTS results provided a comprehensive reaction\npathway: toluene was oxidized to form benzyl alcohol or benzaldehyde\nand then subsequently oxidized to benzoic acid and ultimately converted\nto CO<sub>2</sub> and H<sub>2</sub>O. All these results provided a\nfundamental understanding of the effect of the crystal plane on the\nphotothermal catalysis reaction.