Highly active NbOPO4 supported Cu-Ce catalyst for NH3-SCR reaction with superior sulfur resistance

In this paper, the Cu-Ce based catalyst using NbOPO4 (Nb-P) as support was firstly employed for selective catalytic reduction (SCR) of NO by NH3. The experimental results had illustrated that such catalyst exhibited well SCR activity and N-2 selectivity within a wide temperature range of 200-450 degrees C. These superior performances could be mainly attributed to its improved textural properties and strong acidity derived from NbOPO4 support. More importantly, the sulfur tolerance of the NbOPO4 supported Cu-Ce sample was found greatly improved compared to TiO2 and Ti-Nb supported samples, where above 80% SCR activity of Cu-Ce/Nb-P sample was obtained at 250 degrees C after 10 h reaction running in the presence of 100 ppm SO2. This fact was the result of the enhanced acidity and the strong interactions between Cu-Ce oxides and NbOPO4 support, which could prevent the surface oxygen species from sulfation by SO2. As such, these oxygen species strongly associated with NbOPO4 support still could activate adsorbed NH3 to fulfill the SCR reaction cycle, leading to its better sulfur resistance. The work would provide some enlightenments to the development of NH3-SCR catalysts with high sulfur resistance at medium-high temperature.