Ultra-low loading of copper modified TiO2/CeO2 catalysts for low-temperature selective catalytic reduction of NO by NH3

Abstract A series of ultra-low content copper-modified TiO 2 /CeO 2 catalysts were prepared by wet impregnation method and tested for selective catalytic reduction of NO by NH 3 . The catalyst with a Cu/Ce molar ratio of 0.005 showed the best low-temperature activity and excellent sulfur-poisoning resistance. It was worth noting that the very small amounts of copper addition can lead to three times the activity at low temperature. The prepared catalysts were characterized by XRD, BET, Raman, XPS, NH 3 -TPD and the results revealed that the introduction of copper increased the amount of surface adsorbed oxygen and Ce 3+ species on the catalyst surface and generated more Bronsted acid sites. The redox and surface acidic properties were also improved by the addition of Cu. All these factors played important roles in enhancing NH 3 -SCR performance of TiO 2 -CuO/CeO 2 catalysts. Furthermore, in situ DRIFT experiments demonstrated that Cu doping enhanced the adsorption capacity of NH 3 while the appearance of CuO weakened the adsorption ability of bridging nitrates, both the two factors synergistically facilitated the NH 3 -SCR reaction proceed smoothly via the Eley-Rideal pathway.