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 NOx with NH3 (NH3–SCR), whether the interaction between tungsten (W) and CeO2 could be well established for enhancing SCR performance is still unclear. Herein, W/CeO2 catalysts with different CeO2 morphologies for SCR are fully investigated. Systematic characterization results confirmed that the crystalline WO3 phase was formed on W-loaded CeO2 nanocubes, nanospindles, and nanospheres. Intriguingly, the W/CeO2 nanorods exhibited exclusively polymeric tungstate species. This divergence originates from the distinct W-CeO2 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 NH3–SCR activity followed the order W/CeO2 nanorods > W/CeO2 nanospindles > W/CeO2 nanocubes > W/CeO2 nanospheres. This work reveals the significant role of the CeO2 morphology in the dispersion and interaction of W species, which directly influences the NH3–SCR performance. The insight offers a valuable opportunity for the design of a more efficient SCR catalyst.