Highly active and dispersed copper (Cu) nanoparticles on mesoporous silicas have been prepared via microwave irradiation of a solution of copper precursors with a previously synthesized mesoporous hexagonal silica (HMS) support. The protocol allowed differently low-loaded (typically 0.5 wt%) Cu materials containing Cu metal and small quantities of metal oxides. Materials were then tested as catalysts in the hydrogenation of carbonyl compounds under microwave irradiation. Cu materials were found to be highly active, selective and reusable in the reduction of substituted aromatic ketones and aldehydes, providing quantitative conversion of starting material within 5-10 min reaction at mild reaction conditions with complete selectivity to the alcohols. (C) 2010 Elsevier B.V. All rights reserved.