Gold nanoparticle catalysts for selective hydrogenations
With increasing demand for efficient organic transformations based on the concept of Green Sustainable Chemistry, the development of highly selective reaction systems using heterogeneous catalysts is greatly desired. In selective hydrogenation using heterogeneous catalysts, gold nanoparticle catalysts have recently attracted enormous attention due to their unique catalysis compared with that of conventional hydrogenation catalysts based on Pt, Pd, and Ru nanoparticles. This review describes recent progress in state-of-the-art gold nanoparticle catalysts for chemoselective hydrogenations under liquid-phase conditions. The high and unique catalytic activity of these gold nanoparticles for the hydrogenation of unsaturated carbonyl compounds to unsaturated alcohols, functionalized nitroaromatics to the corresponding anilines, alkynes to alkenes, epoxides to alkenes, amides to amines, etc., is described. The dependence of the high catalytic performance of gold nanoparticles on the metal–support interactions, the morphology (size and shape), and oxidation states is also discussed.