A Comparative Study on the Effect of Surface and Bulk Sulfates on the High-Temperature Selective Catalytic Reduction of NO with NH3 over CeO2

Abstract

Herein, two CeO2 samples dominantly decorated with surface and bulk sulfates were constructed and their distinct effects on high-temperature NH3-SCR were investigated by strictly controlling the sulfate content at a comparable level. The obtainment of surface and bulk sulfates was revealed using a designed leaching experiment, and further evidenced by the characterization results from XPS and H2-TPR. In comparison with CeO2 modified with bulk sulfates (B-CeS), sufficient acid sites with strong intensity were generated on CeO2 modified with surface sulfates (S-CeS). In addition, due to electron-withdrawing effect from S=O in sulfate species, NH3 oxidation over S-CeS was greatly suppressed, providing an additional contribution to enhanced performance in high-temperature NH3-SCR.