Selective catalytic reduction over size-tunable rutile TiO2 nanorod microsphere-supported CeO2 catalysts

Size-tunable 3D rutile TiO2 spheres consisting of nanorods were controllably synthesized by adjusting the precursor hydrolysis rate. CeO2 nanoparticles were supported on TiO2 to prepare a series of Ce/Ti catalysts via an incipient wetness impregnation method. Catalytic activity tests showed that the hierarchical rutile TiO2 microspheres with a size of 1 mu m containing nanorod-supported CeO2 showed excellent activity and high N-2 selectivity over a wide temperature range. The novel morphology of the TiO2 nanostructures exhibits a strong interaction with CeOx species, enhancing their dispersion. The excellent catalytic activity should be mainly attributed to the enriched surface oxygen species, abundant surface acidity and high reducibility. The presence of enriched surface oxygen vacancies could facilitate the formation of active NO2 and bidentate nitrate species, leading to remarkable SCR performances. This was confirmed by in situ DRIFTS investigations.