Effect Of CeO₂ Additive On Supported V₂O₅-CeO₂/TiO₂ Catalysts For The Selective Catalytic Reduction Of NO

The selective catalytic reduction?SCR?is one of the most efficient methods to remove NO_x,and research and development of SCR catalysts with high performances are of great theoretic and practical significances.The promotional eff'ects of CeO₂in the supported V₂O₅-CeO₂/TiO₂ catalysts with different preferentially exposed factes of TiO₂ supports for selective catalytic reduction of NO have been studied in this work by using the micro-tests of selective catalytic reduction?SCR?of NO by NH3 combined with transmission electron microscope?TEM?,BET surface area measurements,X-ray powder diffraction?XRD?,hydrogen temperature-programmed reduction?H₂-TPR?and NH3 temperature-programmed desorption?NH₃^-TPD?It has been shown that adding CeO₂ into the supported V₂O₅/TiO₂?NS?catalyst with preferentially exposed {001} factes,the amount of acidic sites with relatively weak acidity remained almost unchanged,while the amount of acidic sites with relatively weak acidity decreased,and the increase of reducibility of V ions resulted in the increase of N2 selectivity of catalyst.In comparison,adding CeO₂ into the supported V₂O₅/TiO₂?NP?catalyst with preferentially exposed {101} factes resulted in the decreases of acidic sites with weak and strong acidity and the reducibility of V ions,leading to the decreases of NO conversion and N2 selectivity,indicating the different effects of CeO₂ into the supported V₂O₅/TiO₂ catalyst with different preferentially exposed factes of TiO₂ supports.It has been suggested that the CeO₂ components in the supported V₂O₅/TiO₂?NS?catalyst with preferentially exposed {001} factes may involve in the reduction-oxidation cycles of V ions,which exhibits remarkably promotional effects on the V₂O₅/TiO₂?NS?catalysts for SCR reactions.