Characterization and catalytic activity of unpromoted and alkali (earth)-promoted Au/Al_2O_3 catalysts for low-temperature CO oxidation

摘要

Various unpromoted and alkali (earth) promoted gold catalysts were characterized by means of XRD,HRTEM,DR/UV-Vis and TPR.Based on the results we conclude that metallic Au is the active species in CO oxidation and that the reduction of Au~(3+) to Au~0 proceeds below 200 deg C.Pretreatment at mild temperatures,viz.200 deg C,results in the highest catalytic performance of Au/Al_2O_3 in low-temperature CO oxidation.Alkali (earth) metal oxide additives are most probably structural promoters.The best promoting effect is found for BaO.