Pt1In Single Atom Alloy for Visible-Light-Driven CO2 Formylation of Benzylamine

CO₂ formylation of amines provides a promising route to convert CO₂ into value-added chemicals. That process is usually performed through a thermo-catalytic approach with additional reducing agents, which increases the energy consumption and the complexity of the system. Herein, we report photocatalytic CO₂ formylation of benzylamine over Pt₁In-ZnO_x single-atom-alloy catalyst at room temperature in N,N-dimethylformamide (DMF) solvent. The anchoring of Pt single atoms onto In nanoparticles through Pt-In bonds accompanied with electron transfer from In to Pt improves the absorption capacity for visible light and the separation efficiency of photogenerated charge carriers. Furthermore, the adsorption and activation of CO₂ and benzylamine are promoted on the surface of Pt₁In single-atom-alloy. After 6 h reaction under visible-light, the yield of N-benzylformamide reaches 48.6 mmol g^-1 with a 95.3% selectivity. A possible reaction mechanism is proposed based on a series of in situ characterizations and theoretical calculations. A decomposition-regeneration cycle of DMF is involved in the photocatalytic process, which extends the reaction region and thus facilitates the formylation of benzylamine. The photocatalytic system exhibits good cycling stability and universality. This work provides new insights for the rational design of single-atom-alloy catalyst and an efficient approach for the sustainable utilization of CO₂.