Poisoning effect of calcium hydroxide on Fe–Ce/TiO2 catalyst for NO removal: evolution of active species and surface properties

Many SCR catalysts without V species are developed and used for the NO abatement. The content of Ca in the real flue gas will result in the deactivation of catalysts. In this work, the effect of Ca(OH)2 on the denitration performance of the Fe–Ce/TiO2 catalyst for SCR reaction was explored. The BET, XRD, XPS, NH3-TPD, Py-IR, UV–Vis DRS, H2-TPR, and SEM–EDS mapping techniques were used to characterize the evolution of active species and the surface properties over the studied catalysts. The gained results demonstrate that the Ca(OH)2 results in serious deactivation of Fe–Ce/TiO2 catalyst for NH3-SCR reaction and the degree of deactivation is closely related to the loading of Ca(OH)2. Such serious deactivation caused by Ca(OH)2 is attributed to the smaller surface area, the declined redox ability and surface acidity, the lower content of Ce3+ and Fe3+, as well as the less surface adsorbed oxygen species. Moreover, the addition of Ca(OH)2 leads to poor dispersion of Ce and Fe species over the catalyst surface, which may also be responsible for the fall of the catalytic performance of the catalyst