Effect of the pH value of precursor solution on the catalytic performance of V2O5-WO3/TiO2 in the low temperature NH3-SCR of NOx

Abstract

V2O5-WO3/TiO2 catalyst for the selective catalytic reduction of NOx with NH3 (NH3-SCR) was prepared through wet impregnation and characterized by XPS, Raman spectra, H2-TPR, NH3-TPD, NH3-DRIFT, XRD and physical adsorption. The effect of the pH value of vanadium precursor solution on the catalytic performance of V2O5-WO3/TiO2 in the low temperature NH3-SCR of NOx was investigated to optimize the preparation conditions. The results indicated that with the enhancement of precursor solution acidity, more polymeric vanadium species are formed on the catalyst surface; meanwhile, the ratio of V4+(3+)/V5+, surface acidity, and quantity of active sites are increased, whereas the de-NOx performance of the V2O5-WO3/TiO2 catalyst is largely improved. As a result, a V2O5-WO3/TiO2 catalyst with high performance in de-NOx through NH3-SCR can be obtained by enhancing the precursor solution acidity in the preparation process.