Hydrogen treatment-induced surface reconstruction:: Formation of superoxide species on activated carbon over Ag/activated carbon catalysts for selective oxidation of CO in H2-rich gases

Superoxide species were detected on activated carbon (AC) after H-2 treatment at high temperatures (> 300 degrees C) and subsequent oxygen adsorption at 80 degrees C. The introduction of Ag onto the carbon surface promoted the formation of superoxide species. For Ag/AC catalysts, the superoxide species may be able to spill over from the carbon surface to the silver particles and react with CO under reaction conditions; while over AC itself, superoxide species have no activity toward CO oxidation. This is another active oxygen species for CO oxidation over carbon-supported silver catalysts.