Membrane-occluded gold-palladium nanoclusters as heterogeneous catalysts for the selective oxidation of alcohols to carbonyl compounds

Pre-formed polyvinylpyrrolidone-stabilized gold-palladium clusters, consisting of 80 mol% gold and with a mean size of 1.9 nm, were immobilized quantitatively in a porous polyimide membrane via the process of phase inversion, without loss of metal nanodispersion. The obtained goldpalladium/polyimide membrane emerged as a highly active heterogeneous metal catalyst for the amide-phase and solvent-free oxidation of aliphatic, allylic and benzylic alcohols with full selectivity to the corresponding aldehydes and ketones, and could be recycled with excellently preserved catalytic activity and product selectivity. Occlusion of the optimized bimetallic clusters in the polyimide structure proved beneficial in view of their superior catalytic performance compared to the analogous colloidal gold-palladium clusters