Influence of ceria modification on the properties of TiO2-ZrO2 supported V2O5 catalysts for selective catalytic reduction of NO by NH3

TiO2-ZrO2 (hereafter denoted as Ti-Zr) supported V2O5 catalysts with different loadings of CeO2 were synthesized, and their physicochemical properties were characterized by Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), in situ Fourier transform infrared spectroscopy (in situ FT-IR) and temperature-programmed reduction (TPR). Their catalytic activities toward the NOx reduction reaction with NH3 were tested. We found that with the addition of CeO2, more NO was removed in a wide temperature range of 220-500 degrees C. As the CeO2 content was increased from 10% to 20% (i.e., the molar ratio of Ce to Ti-Zr), NO conversion increased significantly; after that, increasing CeO2 content, however, decreased NO conversion. In particular, the addition of CeO2 to V2O5/Ti-Zr suppressed the coke deposition and rendered a stable and high catalytic activity. The characterization results indicated that: (1) the deposited vanadium and cerium oxides were highly dispersed over the Ti-Zr support, and in addition to ZrV2O7, a common binary compound observed in V2O5/Ti-Zr, CeVO4 and Ce3ZrO8 was formed upon increasing CeO2 content; (2) the introduction of CeO2 to V2O5/Ti-Zr sample promoted the redox ability of the resulting catalysts; and (3) the Ce-containing catalysts possessed the greater amount of surface acidic and active intermediate. (C) 2012 Elsevier Inc. All rights reserved.