Novel CeO₂@TiO₂ core-shell nanostructure catalyst for selective catalytic reduction of NOx with NH₃

The CeO₂@TiO₂ core-shell nanostructure catalyst prepared by a two-step hydrothermal method was used for selective catalytic reduction (SCR) of NOx with NH₃ in this study. The catalyst presented the obvious core-shell structure, and the shell was amorphous TiO₂ which could protect the active center from the SO₂ erosion. The catalyst showed high activity and stability, excellent N₂ selectivity and superior SO₂ resistance and H₂O tolerance. Characterizations such as TEM, HR-TEM, XRD, BET, XPS, NH₃-TPD, and H₂-TPR were carried out. The results indicated that the catalyst had large surface area and the active sites were well dispersed on the surface. The NH₃-TPD, H₂-TPR and XPS results implied that its increased SCR activity might be due to the enhancement of NH₃ chemisorption and the increase of active oxygen species, both of which were conductive to NH₃ activation. The excellent catalytic performance suggests that it is a promising candidate for SCR catalyst.