Sunlight-Driven Low-Pressure Dimethyl Carbonate Synthesis via Charge-Asymmetric Cu + –Ce 3+ Sites Enabling Cooperative CO 2 and Methanol Activation

The direct synthesis of dimethyl carbonate (DMC) from CO2 and methanol represents an atom-economic route toward carbon fixation, yet is severely constrained by the inertness of CO2 under low-pressure conditions. Herein, we report a charge-asymmetric Cu+–Ce3+ dual-sites catalyst, constructed by Cu atom integration into CeO2, which enables efficient DMC synthesis under natural sunlight (20 mW/cm2) and low pressure (9 bar). Under these conditions, light primarily serves as a photothermal energy input, while the Cu+–Ce3+ charge-asymmetric interfacial sites govern the reaction pathway and lower the energy barriers of key elementary steps. A high DMC yield of 41.7 mmol/g with ∼100% selectivity was achieved. Our experimental and theoretical prediction results confirmed a cooperative activation mechanism, in which Ce3+ sites facilitate CO2 adsorption and CO2* formation, while electron-deficient Cu+ lowers the energy barrier for CH3O* generation. The proximity of these charge-polarized sites promotes the coupling of CH3O* and CO2* into CH3OCOO* intermediates and enables their facile conversion to DMC. This work not only sets a high catalytic benchmark for the low-pressure photothermal synthesis of DMC but also offers a rational strategy for designing catalysts to convert CO2 into high-value C2+ products.