Integrated DFT and experimental study on Co₃O₄/CeO₂catalyst for direct synthesis of dimethyl carbonate from CO₂

The oxygen deficient site on the catalyst has a strong impact on the activation of CO₂for the synthesis of dimethyl carbonate (DMC). The Co₃O₄/CeO₂catalyst exhibits multiple reduction behavior as cobalt metal species differ in the strength of their interaction with CeO₂. This causes the surface reduction from Ce⁴⁺to Ce³⁺in solid solution Co-O-Ce. The dispersion of Co₃O₄enhanced the formation of oxygen deficient site as revealed by XPS, CO₂-chemisorption and TPR. The non-precious Co₃O₄/CeO₂nanorod was recognized as a potential catalyst for promoting Ce⁴⁺to Ce³⁺for CO₂activation and dimethyl carbonate synthesis (81.5% of yield). Energetics of oxygen vacancy formation of low index surfaces of CeO₂was determined with first-principles calculations based on DFT. Results disclosed the Ce⁴⁺to Ce³⁺formation energy of CeO₂due to Co substitution and corroborated the experimental results. Further, calculations provide the details of the effect of Co substitution on the electronic structure of reduced CeO₂surfaces.