Variant Properties of W Species Over Ceo2 Induced by Different Lattice Planes for Nh3-Scr

Abstract

Although ceria-based catalyst has been proved to be a promising alternative to conventional vanadyl (V)-based catalysts for selective catalytic reduction of NOx with NH3 (NH3-SCR), whether the interaction between tungsten (W) and CeO2 could be well established for enhancing NH3-SCR performance is still unclear. Herein, four kinds of CeO2 with different morphologies (nano-rods, nano-cubes, nano-spheres, and nano-spindles) were firstly synthesized, further loading with W species and used for SCR reaction. Detailed characterization revealed that tungstate rather than WO3 crystal is more likely formed on CeO2 nano-rods. With stronger reducibility, more surface-active oxygen species and acid sites, W/CeO2 nano-rod catalyst exhibited much higher NOx conversion than those of W/CeO2 nano-cubes and W/CeO2 nano-spindles, and the W/CeO2 nano-sphere catalyst exhibited the worst catalytic performance. This work not only clarify the interaction of W species and CeO2 with different morphologies, but also offers a valuable opportunity for the design of more efficient SCR catalyst.

Keywords: W/CeO2 catalyst, morphology effect, NH3-SCR, surface oxygen species