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

Abstract

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 μm containing nanorod-supported CeO₂ showed excellent activity and high N₂ selectivity over a wide temperature range. The novel morphology of the TiO₂ nanostructures exhibits a strong interaction with CeO_x 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.