Selective Catalytic Reduction of NOx Over Nano-Sized Gold Catalysts Supported on Alumina and Titania and Over Bimetallic Gold-Silver Catalysts Supported on Alumina

The reduction of NO with octane under lean conditions was examined over gold supported on alumina and titania and over alumina supported bimetallic gold-silver catalysts. The silver loading was either 1.2 or 1.9 wt% whereas 0.3, 1 or 5 wt% gold was used. The catalysts were characterized by means of EDXS, N-2-adsortion, UV-Vis and TEM to correlate recorded results with different preparation methods. UV-Vis measurements indicated that gold was present in the form of fine Au particles, single Au ions and small (Au)(n)(delta+) clusters on the catalysts and silver was mainly present in the form of single Ag ions. The highest NO to N-2 reduction activity was recorded over the 0.3Au-Al2O3 catalyst. The Au-TiO2 catalysts did not result in significant NO to N-2 reduction.