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 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.