TiO2-modified CeVO4 catalyst for the selective catalytic reduction of NOx with NH3

A series of TiO2-modified CeVO4 catalysts were prepared by the homogeneous precipitation method, among which the CeVTi5 catalyst showed the best low-temperature NH3-selective catalytic reduction (NH3-SCR) activity at high GHSV. The CeVTi5 catalyst also exhibited good H2O and SO2 durability. These catalysts were characterized by XRD, BET, Raman spectroscopy, H-2-TPR, XPS, and NH3-TPD. The introduction of TiO2 into CeVO4 decreased the crystallite size, increased the surface area and the number of acid sites, and promoted the dispersion of active Ce and V species, leading to enhancement of the redox ability and interactions among Ce, V, and Ti, all of which favor the NH3-SCR reaction. According to in situ DRIFTS results, modification with TiO2 increased the number of Lewis acid sites and promoted the adsorption of NOx. The NH3-SCR reaction over the CeVTi5 catalyst followed both the Langmuir-Hinshelwood and Eley-Rideal mechanisms, while only the Eley-Rideal mechanism was observed on the CeVO4 catalyst.