FTIR spectroscopic study of the effects of sulfur poisons on CO adsorption on Cu/SiO2 catalysts

Abstract

IR spectra are reported of CO adsorbed on Cu/SiO2 catalysts in the absence and presence of sulfur dioxide or thiophene. Sulfur dioxide is chemisorbed on reduced copper but does not block the adsorption of CO. However, in the presence of sulfur dioxide surface copper atoms attain cationic character via electron transfer from copper to sulfur dioxide adsorption products. In contrast, adsorbed thiophene not only induces cationic character in exposed copper atoms but also poisons the adsorption of CO.