Nacre-inspired graphene oxide/chitosan supported Pd species composite paper-like membrane with superior catalytic...

Recent studies have shown that graphene oxide (GO) nanosheets can form a nacre-like bioinspired layered structure with polysaccharide of chitosan (CS), leading to composites with excellent mechanical properties. In this study, we go further steps by immobilization of Pd species (both Pd²⁺ and Pd⁰) within nacre-like bioinspired layered GO-CS composite paper-like membranes by vacuum-assisted self-assembly process to fabricate novel GO-CS-Pd composite membrane catalysts for the first time. Synergistic interactions from hydrogen bonding (between the GO nanosheets and CS chains) and ionic bonding (between the GO nanosheets and Pd²⁺ ions) have been efficiently achieved, resulting in significantly improvement of the mechanical properties. Meanwhile, the in-situ grown Pd⁰ nanoparticles were homogeneously incorporated in the interstices of the nacre-like GO-CS composite membranes. The mechanical properties, specific area performances, and Pd⁰ nanoparticles size of the resultant GO-CS-Pd composite membrane are mainly tuned by the loading amount of CS. The membranes are high active for Suzuki reactions of aromatic halides and phenylboronic acid with catalyst loading as low as 0.05 mol%, and can be recycled for 8 runs without significant loss of activities. Positron annihilation lifetime spectroscopy and other structural characterization methods are implemented to characterize the unique compartmentalization structure in the nacre-like composite membranes.