A superior CeO2 @TiO2 catalyst with high dispersion of CeO2 for selective catalytic reduction of NOx with NH3

NOx emissions have raised many environmental problems and posed a serious threat to human health. Development of excellent catalysts for selective catalytic reduction of NOx by NH3 (NH3-SCR) is desirable. In this study, by ingeniously encapsulating Ce ions into MIL-125 channels, CeO2 @TiO2 catalysts were prepared by annealing the Ce/MIL-125 precursor. Due to the porous framework structure of the MIL-125, a large amount of Ce ions were adsorbed into the pores, thus achieving high dispersion of CeO2 in the composites. All the CeO2 @TiO2 catalysts exhibit a NO conversion of nearly 100% at 350 degrees C and a wide temperature range larger than 200 degrees C. The CeO2 @TiO2 (2/3) catalyst shows high specific surface area and porous structure. Meanwhile, a large amount of Ce3+ sites, enriched surface oxygen species, outstanding adsorption of NOx species and high surface acidity for CeO2 @TiO2 (2/3) catalyst account for the excellent NH3-SCR properties with a wide temperature range (200 degrees C similar to 450 degrees C) and excellent H2O and SO2 resistance.

Automated summary

In this study, CeO2 @TiO2 catalysts were prepared by encapsulating Ce ions into MIL-125 channels and annealing the Ce/MIL-125 precursor. The CeO2 @TiO2 catalysts had a NO conversion of nearly 100% at 350 degrees C and a wide temperature range larger than 200 degrees C, attributed to the high dispersion of CeO2 in the composites and the porous structure of CeO2 @TiO2 (2/3) catalyst, which exhibited high specific surface area. Furthermore, the CeO2 @TiO2 (2/3) catalyst had excellent NH3-SCR properties with a wide temperature range (200 degrees C to 450 degrees C) and outstanding resistance to H2O and SO2, thanks to the presence of Ce3+ sites, enriched surface oxygen species, effective adsorption of NOx species, and high surface acidity.