Artificial nacre based on polydopamine functionalized graphene oxide nanosheets constrained palladium nanocluster...

Inspired by "the composition of catechol and amine groups in the adhesive proteins" of marine mussel and "brick-and-mortar" structure of nacre, we use polydopamine (PDA) as "mortar", graphene oxides (GO) nanosheets as "brick", and Pd²⁺ ions as interfacial reinforcer, to fabricate nacre-like Pd²⁺ enhanced PDA functionalized GO membranes (Pd@PDA/GO) with vacuum filtration-assisted assembly method. Meanwhile, in situ reduced Pd⁰ nanoclusters by PDA chains were well constrained within the resultant Pd@PDA/GO artificial nacre composites. Good interfacial adhesion with dense packing of the GO nanosheets was further confirmed with sub-nano level microstructure characterization by positron annihilation lifetime spectroscopy. The microstructural evolution of the laminated composites has been probed in depth from a theoretical computational point of view using molecular dynamics (MD) simulations. The optimal Pd@PDA5/GO95 artificial nacre composite exhibits highest tensile strength of 151.6 MPa, about three times of staring GO membranes. Using as low as 0.03 mol% of Pd@PDA5/GO95 catalyst, Suzuki coupling reaction of aryl halides with phenylboronic acid can be efficiently catalyzed and recycled for 6 runs with excellent yield.