Engineered Asymmetric Ceδ+-O-P Structures via CeO2-CePO4 Heterojunctions for Continuous Dimethyl Carbonate Synthesis from CO2 and Methanol

Chemical fixation of CO2 with CH3OH into value-added chemicals, such as dimethyl carbonate (DMC), plays a crucial role in carbon neutrality and resource recycling. However, its efficiency is limited by the ineffective synergistic activation of CO2 and CH3OH. Here, we employ a strategy to construct CeO2-CePO4 heterojunctions by phosphate-functionalized CeO2, introducing an asymmetric Ceδ+-O-P structure for CO2 and CH3OH activation. The prepared Ce0.8P0.2Oσ catalyst achieves a CH3OH conversion of 28.6% with nearly 100% DMC selectivity and retains its performance for 300 h during continuous DMC synthesis at 140 °C. Experimental characterization supports the formation of local Ceδ+-O-P sites in the catalyst. DFT calculations based on one selected idealized strained model containing a specific local Ceδ+-O-P site show a distinct Bader charge for Ce–O–P and Ce–O–Ce coordinated oxygen atoms within this model. Within the same model, the local Ceδ+-O-P site is associated with elongation of the C–O bond in CH3O* and a lower energy barrier for its dissociation into *CH3 and *O, providing a model-specific interpretation of the enhanced DMC yield. This work develops a design strategy for asymmetric catalytic site via composite oxide heterojunctions engineered for CO2 and CH3OH activation, exhibiting great potential for large-scale continuous CO2 chemical fixation to high-value-added chemicals.