A MnO_x@Eu-CeO_x nanorod catalyst with multiple protective effects: Strong SO₂-tolerance for low temperature DeNO_x...

A novel MnO_x@Eu-CeO_x catalyst with multiple protective attributes was designed and fabricated using a chemical precipitation method and tested for its low temperature SCR activity. The subject MnO_x@Eu-CeO_x nanorod catalyst exhibited superior SCR performance and strong SO₂-tolerance. The formation of the composite-shell structure enhanced the catalysts' surface acidity and redox performance, which resulted in excellent SCR performance. Moreover, the TG results suggested that the protective effect of the EuO_x-CeO_x composite-shell effectively reduced the deposition of the surface sulphates. The XPS, XRD analysis results of the subject catalyst together with theoretical calculations provided strong evidence that there was a strong interaction between Mn and Ce in the MnO_x@Eu-CeO_x. This significant interaction could provide maximum protection to the core from the effect of SO₂, which also contributed to the high SO₂ resistance of the catalyst. In situ FT-IR results also indicated that the chemisorbed species on MnO_x@Eu-CeO_x were much more stable in the presence of SO₂ compared to Eu-CeO_x/MnO_x, which resulted in the deposition of significantly less sulphates. This low temperature SCR catalyst with multiple protective attributes, including composite shell, strong interaction and core-shell structure, is the key to long-term resistance to SO₂.