Effect of gas composition on the selective reduction of $NO_x$ with ammonia over Vanadia based catalysts

Abstract

The catalytic reduction of $NO_x$ under different oxygen concentrations leading to different NO/$NO_2$ compositions hasbeen studied in the presence of V3W9Ti and V8W9Ti catalysts in a tubular flow reactor. The results have shown thatincreasing $O_2$ concentration leads to increase the $NO_x$ reduction in low temperature range [150-275 °C]. Slight effectof $O_2$ concentration on $NO_x$ conversion was observed at higher temperatures. SCR reaction also occurred in theabsence of gaseous oxygen but with low NO conversion indicating the strong redox properties of both catalysts. Agedcatalysts exhibited relative good activities in $NO_x$ reduction. This is probably due to the sol gel method used for thepreparation of the catalysts known to improve the catalysts properties.