Deactivation mechanism of commercial V2O5-MoO3/TiO2 SCR catalyst by arsenic poisoning in coal-fired power plants

Arsenic, a toxic component in coal-fired flue gas, is poisonous to the commercial selective catalytic reduction (SCR) denitrification catalysts. To unveil the arsenic poisoning mechanism on commercial SCR catalysts, fresh and one-year-used arsenic-poisoned plate-type V2O5-MoO3/TiO2 catalysts from a coal-fired power plant in Inner Mongolia Province of China were systematically analyzed with SCR activity and characterization experiments. The results indicated that the plate-type V2O5-MoO3/TiO2 catalysts possessed a certain ability to resist arsenic poisoning. The average denitrification efficiency of the poisoned catalysts maintained over 70% at 350 °C even though the arsenic content was as high as 7 wt%, compared with the denitrification efficiency of 87.35% for the fresh catalyst. Characterization results indicated that both physical and chemical factors resulted in the deactivation of catalysts by arsenic. The surface area and amount of surface acid sites of the used catalysts decreased, which inhibited ...