Insight into the SO2 poisoning of heterobimetallic FeCu‐SSZ‐13 zeolite in NH3‐SCR reaction

Abstract The SO 2 poisoning of a heterobimetallic FeCu‐SSZ‐13 in selective catalytic reduction of NO with NH 3 (NH 3 ‐SCR) was systematically investigated in this study. It was shown that when SO 2 is involved in the feeding flue gas, the losses in the redox ability of active metals (primary contributor to deactivation) and in the number of Brønsted acid sites both inhibit the formation of NH 4 NO 2 intermediate, resulting in the rapid deactivation of FeCu‐SSZ‐13. The SO 2 poisoning of FeCu‐SSZ‐13 at low temperature is more serious than at high temperature, because of the more severe loss of redox ability of active metals. Unlike that of monometallic Cu‐/Fe‐CHA, the SO 2 poisoning of the bimetallic one is saliently featured by that partial SO 2 is oxidized to SO 3 and partial Brønsted acid sites are destroyed due to the formation of H 2 SO 4 . This work may provide a fundamental understanding on the SO 2 poisoning of heterobimetallic zeolite‐based NH 3 ‐SCR catalysts.