HIGH SO₂-TOLERANCE OF Pt-LOADED AlPO₄ CATALYST FOR SELECTIVE CATALYTIC REDUCTION OF NITROGEN MONOXIDE BY ETHENE IN EXCESS OXYGEN

Abstract

The catalytic activity of Pt/AlPO₄ for C₂H₄-NO-O₂ in the presence of SO₂ was found to be higher in terms of the maximum NO conversion and the corresponding temperature than that of Pt/Al₂O₃. The selectivity toward N₂O (byproduct) of Pt/AlPO₄ was depressed by the presence of SO₂ to its advantage; while the selectivity of Pt/Al₂O₃ was almost unaffected. The XPS spectra of Al, P and O of Pt/AlPO₄ were hardly affected even by the presence of SO₂. On the other hand, the XPS spectra of Al and O of Pt/Al₂O₃ were evidently affected by the presence of SO₂, suggesting that SO₂ interacted strongly with the Al₂O₃ to form aluminum sulfate-like species. The high SO₂-tolerance of Pt/AlPO₄ could be ascribed to the low reactivity of AlPO₄ with SO₂.