Dimethyl carbonate synthesis from CO 2 and methanol over CeO 2 : elucidating the surface intermediates and oxygen vacancy-assisted reaction mechanism.

Surface intermediate species and oxygen vacancy-assisted mechanism over CeO 2 catalyst in the direct dimethyl carbonate (DMC) synthesis from carbon dioxide and methanol are suggested by means of transient spectroscopic methodologies in conjunction with multivariate spectral analysis. How the two reactants, i.e. CO 2 and methanol, interact with the CeO 2 surface and how they form decisive surface intermediates leading to DMC are unraveled by DFT-based molecular dynamics simulation by precise statistical sampling of various configurations of surface states and intermediates. The atomistic simulations and uncovered stability of different intermediate states perfectly explain the unique DMC formation profile experimentally observed upon transient operations, strongly supporting the proposed oxygen vacancy-assisted reaction mechanism.