Regeneration and sulfur poisoning behavior of In/H-BEA catalyst for NOx reduction by CH4

Sulfur poisoning and regeneration behavior of In/H-BEA catalyst were carried out in NOx reduction by CH4. In/H-BEA catalyst exhibited a poor resistance to sulfur dioxide after addition of 200 ppm SO2 and 10 vol.% H2O into NO reduction with CH4 at 450 degrees C for 45 h. Sulfur poisoning of In/H-BEA was attributed to the inhibition of NOx adsorption on Bronsted acid sites, suppression of reaction intermediates generation on the active sites, and the formation of surface sulfate species. The formation of surface sulfate reduced the availability of surface active sites, blocked the pore structure and decreased the surface area of catalyst. These changes in chemical and textural properties resulted in a severe loss in the activity of sulfated In/H-BEA catalyst for NO reduction with CH4. H-2 reduction is a promising technology for regeneration of In/H-BEA deactivated by SO2 for removing NOx from lean-burn and diesel exhausts. Indium sulfate could be reduced by H-2 to InO+ with In2O3 and In(OH)(2)(+) as the intermediates. The optimal parameters of H2 reduction was regeneration temperature of 400 degrees C and regeneration time of 60 min which completely recovered the catalytic activity of In/H-BEA. (C) 2016 Elsevier B.V. All rights reserved.