Influence of Ageing, Silver Loading and Type of Reducing Agent on the Lean NO x Reduction Over Ag–Al2O3 Catalysts

Abstract

The influence of ageing temperature, silver loading and type of reducing agent on the lean NOx reduction over silver–alumina catalysts was investigated with n-octane and bio-diesel (NExBTL) as reducing agent. The catalysts (2 and 6 wt% Ag–Al2O3) were prepared with a sol–gel method including freeze drying and the evaluation of NOx reduction and aging were performed using a synthetic gas-flow reactor. The results indicate a relatively high NOx reduction for both reducing agents. The hydrothermally treated 6 wt% Ag–Al2O3 sample displays a maximum NOx reduction of 78 % at 350 °C for n-octane as reductant and the corresponding value for NExBTL is 60 %. Furthermore, the catalysts show high durability and an increase in activity for NOx reduction after ageing at temperatures up to 650 °C, with n-octane as reducing agent.