The effect of Cr addition on Hg0 oxidation and NO reduction over V2O5/TiO2 catalyst

Abstract

A series of V2O5-Cr2O3/TiO2 catalysts with various chromium loadings prepared by the impregnation method were studied for Hg0 oxidation and NO reduction. The results indicate that Cr2O3-modified V2O5/TiO2 exhibited improved catalytic activity for both Hg0 oxidation and NO reduction. In fact, with the addition of 5% Cr2O3 to the V/Ti catalyst, the mercury oxidation efficiency increased significantly from 6.5% to 97% in the presence of O2 at 350°C, and its SCR performance also improved in the temperature range of 250°C to 400°C. To explore the effect of individual flue gas components on Hg0 oxidation, a series of activity tests were conducted over 1% Cr-V/Ti at 350°C, and it was found that O2 and HCl promote mercury oxidation, while SO2 and H2O exhibited a somewhat inhibitive influence. H2-TPR and XPS results indicated that the enhanced catalytic performance of V2O5-Cr2O3/TiO2 is attributable to the synergetic interactions between the two active phases.