Effect of redox treatments on activation and deactivation of gold nanospecies supported on mesoporous silica in CO oxidation

► Catalytic performance of mesoporous Au/HMS catalysts in the CO conversion. ► Effect of activation and deactivation of Au catalysts under redox treatments. ► Cationic Au species as active sites in the CO oxidation to low temperatures. ► Au metallic particles as active sites in the CO oxidation to high temperatures.