LAUSR

Few-layered graphene-supported 1.1.1 and 2.0.0 oriented Au and Cu2O nanoplatelets were prepared by one-step pyrolysis of the corresponding metal salts embedded in chitosan at 900 °C under inert atmosphere. These nanometric films containing oriented nanoplatelets were investigated in a series of reactions as Ullmann-type homocoupling, C–N cross-coupling and Michael addition. The catalysts exhibited turnover numbers (TONs) three to six orders of magnitude higher than those of analogous graphene-supported unoriented metal nanoparticles. In addition it has been found that oriented Cu2O and Au nanoplatelets grafted on defective graphene also exhibit activity to promote the Michael addition of compounds with active methylene and methine hydrogens to α,β-conjugated ketone. An exhaustive characterization of these materials using spectroscopic and electron microscopy analyses has been carried out. CO2 thermoprogrammed desorption measurements show that films of these two graphene supported catalysts exhibit some basicity that can explain their activity to promote Michael addition.