One pot synthesized CeO2-WO3-TiO2 catalysts with enriched TiO2 (0 0 1) facets for selective catalytic reduction of NO with NH3 by evaporation-induced self-assembly method

Abstract

CeO2-WO3-TiO2 catalysts were directly synthesized by evaporation-induced self-assembly (EISA) method and used for selective catalytic reduction of NO with NH3. The percentage of enriched TiO2 (001) facets on CeO2-WO3-TiO2 catalysts were modified by the P123:Ti ratio. While the P123:Ti ratio was 0.02, the percentage of enriched TiO2 (001) facets were the maximum on CeO2-WO3-TiO2 catalysts. At this condition, the catalytic activity and the percentage of TiO2 (001) facets presented linear relationship. With the increase of the percentage of TiO2 (001) facets, catalytic activity of catalysts presented a rising trend. Thus CeO2-WO3-TiO2-0.02 catalyst showed the best catalytic activity for selective catalytic reduction of NO with NH3. Besides, the modulation of P123:Ti ratio could also influence the reducing capacity and acid sites for catalysts, which would promote catalytic activity of catalysts. Based on those influence factors, CeO2-WO3-TiO2-0.02 catalyst showed the best catalytic activity. Simultaneously, CeO2-WO3-TiO2-0.02 catalyst showed excellent resistance of H2O and SO2. Various characterization results indicated that the surface atomic ratio of Oβ/(Oα + Oβ) had a certain decrease for poisoned catalyst, which would result in the decrease of low-coordinated atoms on TiO2 (001) facets. At the same time, when pumped of H2O and SO2, the ammonium sulfate salt deposition and competitive adsorption of SO2 and NO would occur so that result in the decrease of catalytic activity.