Engineering electrophilic atomic Ir sites on CeO_(2) colloidal spheres for selectivity control in hydrogenation of α,β-unsaturated carbonyl compounds

Selective hydrogenation of the carbonyl bond inα,β-unsaturated carbonyl compounds is rather challenging owing to the more feasible hydrogenation of ethylenic bond from both thermodynamic and kinetic aspects.Here,we demonstrate a facile emulsionbased molecule-nanoparticle self-assembly strategy for the atomic engineering of Ir species on three-dimensional CeO_(2)spheres(Ir1@CeO_(2)).When applied to the hydrogenation ofα,β-unsaturated aldehydes,Ir1@CeO_(2)catalyst remarkably exhibited~100%selectivity towards unsaturated alcohols,whereas the formation of Ir nanoparticles on CeO_(2)drastically decreased the selectivity for unsaturated alcohols.Spectroscopic studies revealed that strong metal-support interactions triggered the charge transfer from Ir to CeO_(2),leading to the partial reduction of Ce^(4+)to Ce^(3+)along with the formation new Ir^(δ+)-O_(2)--Ce^(3+)(OV)interfaces.The electrophilic atomic Ir species at the Ir^(δ+)-O_(2)--Ce^(3+)(OV)interfaces would therefore preferentially adsorb and facilitate hydrogenation of polar C=O bond to achieve exceptional selectivity.