Metal-oxide interactions modulating the activity of active oxygen species on atomically dispersed silver catalysts.

The activity of active oxygen species on supported Ag atoms can be effectively modulated by metal-support interactions using different oxide supports. The strong interaction between Ag and Al 2 O 3 with more electrons transferred from Ag to Al 2 O 3 leads to the formation of more Ag-O 2 - (superoxide) species, responsible for the selective oxidation of ethylene to ethylene oxide. The relatively weak interaction between Ag and SiO 2 induces the generation of Ag-O (atomic oxygen) and Ag-O 2 2- (peroxide) species, which are more active for complete oxidation of CO and ethylene to CO 2 . This work is of significance for deep understanding of active surface species in atomically dispersed metal catalysts.