Ceria-zirconia supported Au as highly active low temperature Water-gas shift catalysts

摘要

Au/CeZrO_4 catalysts have shown very low temperature activity for the WGS reaction. Characterisation of the as-prepared catalysts shows Au is present primarily as isolated Au~(3+) atoms. It has been found that a higher proportion of Au~(3+) present in the as-prepared catalyst leads to a higher WGS activity, although under reaction conditions reduction to Au° is observed. Use of TPR and iso-thermal H2O re-oxidation has shown that Au reacts with H2O at lower temperatures than an equivalent Pt/CeZrO_4 catalyst, indicating that H2O activation is key in the onset of low temperature WGS activity.