Boosting CO ₂ Fixation into Dimethyl Carbonate via Multiple Active Sites Constituted by V _O‐Ce‐O Vacancy Clusters on Single‐Unit‐Cell CeO ₂ Nano‐Sheets

The thermodynamic stability and intrinsic kinetic inertia of CO₂ present a critical challenge for its effective activation in the synthesis of high-value dimethyl carbonate (DMC). In this work, we report the fabrication of novel O-Ce-O vacancy clusters (V_O-Ce-O) incorporated into CeO₂ nano-sheets with a near single-unit-cell thickness to construct atomically adjacent multiple active sites on their surfaces. These active sites significantly enhance the activation of both CO₂ and CH₃OH. Impressively, the as-prepared CeO₂ with V_O-Ce-O catalyst exhibits an excellent DMC yield of 31.2 mmol g^-1, surpassing previously reported Ce-based catalysts under equivalent reaction conditions. Experimental results and theoretical calculations reveal that oxygen vacancy increases the reducibility of lattice oxygen, facilitating CO₂ activation, while cerium vacancies weaken the *CH₃O adsorption, promoting the coupling reaction between *CH₃O and *CO₂ to form the intermediate (*CH₃OC(O)₂). Notably, the formation of vacancy clusters reduces the energy barrier for the rate-controlled step (*CH₃OC(O)₂ dissociation to *CH₃OCO), thereby boosting the DMC yield. Our new findings provide valuable insights into surface engineering and active site modulation of cerium-based catalysts, offering a viable pathway for green resource utilization of CO₂.