The effect of oxygen vacancy at CO oxidation on anatase (001)-supported single-Au catalyst

The catalytic performance of CO oxidation on the TiO2-supported gold catalysts would be affected by the O vacancies on a TiO2 surface. First-principle studies here are focused on how the O vacancy addresses the performance of single atom catalysts on CO oxidation. Three possible configurations of gold adatoms and O vacancies on anatase TiO2 (001) support are considered as follows: A gold adatom above an O vacancy, a gold adatom or two gold adatoms above an O vacancy dimer. The O vacancy dimer favors the binding of negatively charged gold adatoms on anatase TiO2(001) support. However, the dual gold adatoms slightly increase the barrier energy in CO oxidation through the Au-assisted Mars-van Krevelen mechanism. The formation of a stable carbonate on the initial-existing O vacancy reveals that the extra O vacancy deteriorates the catalytical performance of CO oxidation. In final, the high catalytic performances of TiO2/Au catalyst are attributed to the synergistic effects between a negatively charged Au adatom and a lower-coordinated Ti3+ ion.