Boosting CO2 Fixation into Dimethyl Carbonate via Multiple Active Sites Constituted by VO‐Ce‐O Vacancy Clusters on Single‐unit‐cell CeO2 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 (VO‐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 VO‐Ce‐O catalyst exhibits an excellent DMC yield of 31.2 mmol/g, 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.