Abstract

Sulfates formed on the catalyst surface have been the main cause of its rapid deactivation during the NH3-SCR reaction. Here, after loading ABS onto nanotube structured Ce-Mn-TNTs and nanoparticle CeMnTiOx catalysts, the low-temperature activities of the catalysts deactivated rapidly. After in situ decomposition of ABS on the catalyst surface under the reaction atmosphere, it was found that the de-NOx efficiency of the regenerated Ce-Mn-TNTs-R catalyst was significantly restored. This was mainly attributed to the lower vapor pressure inside the nanotube structure compared to nanoparticles, which promoted the rapid decomposition of ABS. In addition, the decomposition process of ABS was accompanied by the formation of metal sulfates, which disrupted the redox cycle between the active metals, causing a certain inhibitory effect on the recovery of catalytic activity. However, the presence of SO42- improved the content of chemisorbed oxygen on the nanotube structured catalyst surface and increased the numbers of Br & oslash;nsted acid sites on the catalyst surface, which enhanced the adsorption capacity of the Ce-Mn-TNTs catalyst for NH3 and was favorable for the recovery of catalytic activity. Thus, the presence of sulfates on the surface of nanotube structured catalysts had contradictory effects in the NH3-SCR reaction process. The surface interface of nanotube structured catalysts is extremely advantageous for the decomposition of ABS. The above findings provided reliable theoretical bases for the design of catalysts with good SO2 tolerance.

Keywords Plus：SOLVOTHERMAL SYNTHESIS，TITANIUM CATALYSTS，MN/TIO2 CATALYSTS，REDUCTION，NOX，CE，OXIDE，SO2，NH3，MN

Published in CATALYSIS SCIENCE & TECHNOLOGY；10.1039/d4cy01292e