Variant Properties of Tungsten Species over CeO2 Induced by Different Lattice Planes for the Selective Catalytic Reduction of Nitric Oxide

Although ceria-based catalysts have been proven to be a promising alternative to conventional vanadyl catalysts for the selective catalytic reduction of NO x with NH 3 (NH 3 –SCR), whether the interaction between tungsten (W) and CeO 2 could be well established for enhancing SCR performance is still unclear. Herein, W/CeO 2 catalysts with different CeO 2 morphologies for SCR are fully investigated. Systematic characterization results confirmed that the crystalline WO 3 phase was formed on W-loaded CeO 2 nanocubes, nanospindles, and nanospheres. Intriguingly, the W/CeO 2 nanorods exhibited exclusively polymeric tungstate species. This divergence originates from the distinct W-CeO 2 interaction mediated by preferentially exposed {110} lattice planes, endowing the nanorod catalyst with stronger reducibility, more surface-active oxygen species, and acid sites. Consequently, the NH 3 –SCR activity followed the order W/CeO 2 nanorods > W/CeO 2 nanospindles > W/CeO 2 nanocubes > W/CeO 2 nanospheres. This work reveals the significant role of the CeO 2 morphology in the dispersion and interaction of W species, which directly influences the NH 3 –SCR performance. The insight offers a valuable opportunity for the design of a more efficient SCR catalyst.