Dimethyl Carbonate Synthesis from CO 2 over CeO 2 with Electron-Enriched Lattice Oxygen Species.

Direct synthesis of dimethyl carbonate (DMC) from CO 2 plays an important role in carbon neutrality, but its efficiency is still far from the practical application, due to the limited understanding of the reaction mechanism and rational design of efficient catalyst. Herein, abundant electron-enriched lattice oxygen species were introduced into CeO 2 catalyst by constructing the point defects and crystal-terminated phases in the crystal reconstruction process. Benefitting from the acid-base properties modulated by the electron-enriched lattice oxygen, the optimized CeO 2 catalyst exhibited a much higher DMC yield of 22.2 mmol g -1 than the reported metal-oxide-based catalysts at the similar conditions. Mechanistic investigations illustrated that the electron-enriched lattice oxygen can provide abundant sites for CO 2 adsorption and activation, and was advantageous of the formation of the weakly adsorbed active methoxy species. These were facilitating to the coupling of methoxy and CO 2 for the key *CH 3 OCOO intermediate formation. More importantly, the weakened adsorption of *CH 3 OCOO on the electron-enriched lattice oxygen can switch the rate-determining-step (RDS) of DMC synthesis from *CH 3 OCOO formation to *CH 3 OCOO dissociation, and lower the corresponding activation barriers, thus giving rise to a high performance. This work provides insights into the underlying reaction mechanism for DMC synthesis from CO 2 and methanol and the design of highly efficient catalysts.