文摘
Ag/Al<sub>2sub>O<sub>3sub> catalysts modified by Si, Ti, Mg and W were studied to obtain higher NO<sub>xsub> SCR activity and potentially also higher SO<sub>2sub> resistance than the pure silver-based catalyst for automotive applications. Addition of Ti or Si to the alumina support leads to a better NO<sub>xsub> removal at low temperature i.e. reduces the SCR onset temperature by about 10 掳C under the applied conditions. However, it does not increase the SO<sub>2sub> resistance. The catalysts and the supports have been characterized by BET, conventional and synchrotron XRD, X-ray absorption spectroscopy during temperature-programmed reduction (XAS-TPR) and temperature-programmed desorption of ammonia (NH<sub>3sub>-TPD). The obtained results suggest a better silver dispersion and better regeneration capability in the case of Ti- and Si-modified Ag/Al<sub>2sub>O<sub>3sub> catalysts.