CuO supported on mesoporous silica SBA-15 was investigated as a catalyst for selective catalytic reduction of NO by CO. The CuO/SBA-15 catalysts were prepared by wet impregnation with copper loadings of 4.01-10.1 wt%. The catalysts were characterized by N(2) adsorption, XRD, ICP, H(2)-temperature programmed reduction (TPR) and NO-temperature programmed desorption. The most active CuO/SBA-15 catalyst in this study was Cat-B, containing 8.67 wt% Cu on silica. This catalyst achieved 60% NO reduction in catalytic tests. Increasing the Cu loading to 10.1 wt% resulted in a less active catalyst (Cat-C) than for Cu loadings less than 10 wt%. The reduced activity of Cat-C for the NO + CO reaction was attributed to formation of bulk CuO aggregates on the SBA-15 particles and a Cu(2)O phase at high Cu loadings, as confirmed by TPR experiments and XRD measurements. (C) 2010 Elsevier B.V. All rights reserved.