SO2- and H2O-Tolerant Catalytic Reduction of NOx at a Low Temperature via Engineering Polymeric VOx Species by CeO2.

ABSTRACT

Selective catalytic reduction (SCR) of NOx over V2O5-based oxide catalysts has been widely used, but it is still a challenge to efficiently reduce NOx at low temperatures under SO2 and H2O co-existence. Herein, SO2- and H2O-tolerant catalytic reduction of NOx at a low temperature has been originally demonstrated via engineering polymeric VOx species by CeO2. The polymeric VOx species were tactfully engineered on Ce-V2O5 composite active sites via the surface occupation effect of Ce, and the obtained catalysts exhibited remarkable low-temperature activity and strong SO2 and H2O tolerance at 250 °C. The strong interaction between Ce and V species induced the electron transfer from V to Ce and tuned the SCR reaction via the E-R pathway between the NH4+/NH3 species and gaseous NO. In the presence of SO2 and H2O, the polymeric VOx species had not been hardly influenced, while the formation of sulfate species on Ce sites not only promoted the adsorption of NH4+ species and the reaction between gaseous NO and NH4+ but also facilitated the decomposition of ammonium bisulfate through weakening the strong bond between HSO4- and NH4+. This work provided a new strategy for SO2- and H2O-tolerant catalytic reduction of NOx at a low temperature.