Electron Regulation of Single Indium Atoms at the Active Oxygen Vacancy of In2O3(110) for Production of Acetic Acid and Acetone through Direct Coupling of CH4 with CO2

The production of acetic acid and acetone from the direct coupling of CO2 and CH4 on the doped In2 O3 (110) surface has been studied by extensive first-principles calculations, and the Ga or Al substitution for the single In atom at the active oxygen vacancy of In2 O3 (110) can stabilize the reaction species and reduce the free energy barrier of the rate-limiting C-H activation for the conversion of CO2 and CH4 to acetic acid. Herein, the metal doping lowers the energy level of partially empty s and p orbitals of In1 at the oxygen vacancy site and manipulates its electronic properties, resulting in the activity improvement. The stable intermediate with the newly-formed CH3 COO* has the available In1 site for subsequent CH4 activation, which may initiate the direct C-C coupling of CH3 COO* and CH3 * to yield C3 species on the doped In2 O3 (110). These findings suggest that the metal doping of the active oxygen vacancy opens an avenue for the carbon-chain growth through heterogeneously catalytic coupling of CO2 and CH4 .