Selective Catalytic Reduction of NO x Over Nano-Sized Gold Catalysts Supported on Alumina and Titania and Over Bimetallic Gold–Silver Catalysts Supported on Alumina

Abstract

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, N2-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 δ+ clusters on the catalysts and silver was mainly present in the form of single Ag ions. The highest NO to N2 reduction activity was recorded over the 0.3Au–Al2O3 catalyst. The Au–TiO2 catalysts did not result in significant NO to N2 reduction.