Pretreatment effect on copper-titanium dioxide catalysts in CO oxidation

Copper-titanium dioxide (Cu-TiO2) catalysts are pretreated with hydrogen-helium and oxygen-helium before evaluation of the carbon monoxide oxidation. Pre-reduced Cu-TiO2 catalysts showed higher initial and overall activity than pre-oxidized Cu-TiO2 catalysts. H2-TPR results revealed that copper species are dispersed differently after pre-reduction and pre-oxidation treatments. XPS results confirmed that Cu+ and Cu2+ species exist for both treatments. Meanwhile, IR results suggested Cu+ species promote the absorption of CO, leading to increased reaction rates.