Sulfur tolerance of Cu- and H-mordenite zeolite catalysts for the reduction of NO by hydrocarbons

Sulfur tolerances of Cu- and H-mordenite zeolite catalysts prepared by ion-exchange were examined in a fixed-bed now-reactor system. Rates of reduction of NO over HM or CuHM with C2H4 and CuNZA with C3H6 are decreased by SO2 included in the feed gas stream. Surface areas and sulfur contents of the deactivated catalysts, their TGA and TPSR patterns and observations by XPS and Raman suggest the formation of a sulfur species on the catalyst surface in the form of sulfate (SO42-) which causes the loss of NO removal activity of the catalysts. Data from Cu K-edge absorption spectra suggest sulfur electrostatically interacts with Cu ions on the catalyst surface.