Insight into the catalytic performance and NH_3 adsorption under high concentration of CO_2 and/or H_2O conditions on selective catalytic reduction of NO by NH_3 over V_2O_5-WO_3/TiO_2 catalyst

摘要

Under various combustion process, CO2 and H2O both would exist in flue gas, the understanding of the influence mechanism of high concentration of CO2 and H2O on V2O5-WO3/TiO2 catalysts can provide needed information for the achievement of ultra-low emission. This study predominantly investigated NH3 adsorption and catalytic performance of V2O5-WO3/TiO2 catalyst under high concentration of CO2 and H2O conditions. Analyses of XRD, NH3-TPD, XPS and DRIFTS were performed to characterize the catalyst properties. Results show that the reaction between NO and NH3 followed E-R mechanism, CO2 and H2O mainly affect NO conversion by influencing the proportion of O alpha, proportion of V4+ and NH3 adsorption, which would hardly change the physical and crystalline structure of the catalyst. NH3 adsorption on catalysts is complicated under CO2 and H2O conditions. The net effect of CO2 on NH3 adsorption was negligible, and H2O inhibited NH3 adsorption generally. Although the addition of 25%H2O increased the proportion of O alpha on catalyst by forming hydroxy groups, the decreasing of V4+ proportion and NH3 adsorption play dominant roles in NO removal process, resulting in the significantly decrease of NO conversion under H2O-containing atmospheres.