Ce O P material supported CeO2 catalysts: A novel catalyst for selective catalytic reduction of NO with NH3 at low temperature

In this paper, CeOP material (mainly consisted of CePO4) and TiO2 supported CeO2 catalysts were prepared by wet impregnation route for the selective catalytic reduction (SCR) of NO with NH3. The SCR activity results had revealed that CeO2/CeOP-0.4 catalyst yielded over than 90% NO conversion within the temperature range of 200–300 °C, whereas the deNOx efficiency of CeO2/TiO2-0.4 catalyst was less than 30% at 200 °C. After a series of characterization tests, it was found that CeO2/CeOP catalysts were of better dispersion of active phase than CeO2/TiO2 owing to the strong interactions between CeO2 and surficial CeO species on CeOP material. Thus, more active oxygen species could participate in the SCR reaction at low temperature. Furthermore, compared to CeO2/TiO2 sample, the surface acidity was greatly enhanced for CeO2/CeOP catalysts by the introduction of the acidic support, benefiting the adsorption of NH3. Both of which were attributed to the main reasons of the promoted SCR performance over CeO2/CeOP catalysts. Moreover, the NOx ad-species on CeO2/TiO2 sample were very stable and could hardly react with adsorbed NH3, impeding L-H reaction pathway at low temperature.