The promoting effect of palygorskite on CeO2-WO3-TiO2 catalyst for the selective catalytic reduction of NOx with NH3

A series of CeO2-WO3-Pal/TiO2 catalysts were prepared by doping with different contents of palygorskite (Pal). More importantly, the CeO2-WO3-20%Pal/TiO2 catalyst prepared by impregnation method showed excellent performance for selective catalytic reduction (SCR) NOx with NH3. In more detail, the NO conversion could reach to 82% at 240 degrees C and keep above 92% in the range of 280-400 degrees C. According to the NH3-TPD tests, the surface acidity of the CeO2-WO3-20%Pal/TiO2 catalyst was increased obviously, which is beneficial to the NH3 adsorption in the SCR reaction. Besides, through XRD, XPS, Raman spectra and TEM characterizations, it suggested that the active species cerium and tungsten were uniformly dispersed on the surface of Pal, and it is very important for the improvement of SCR performance. In a word, the optimum Pal proportion was helpful to improve the catalyst catalytic performance, so it was more widely used in the SCR process.