Mussel-Inspired Catechol-Formaldehyde Resin Coated Fe3O4 Core-Shell Magnetic Nanospheres: An Effective Catalyst Support for Highly Active Palladium Nanoparticles.

Magnetic Fe3O4@catechol-formaldehyde resin (CFR) core-shell nanospheres were fabricated via a controllable hydrothermal method. The shell thickness of Fe3O4@CFR nanospheres can be effectively regulated in the range of 10~170 nm via adjusting reaction parameters. Especially, catechol groups on the surface of nanospheres also play a significant role in mussel-inspired chemistry to further combine with graphene oxide (GO) to wrap the Fe3O4@CFR spheres. The obtained Fe3O4@CFR and Fe3O4@CFR@GO nanospheres can be used as the effective catalyst supports of small Pd nanoparticles ( < 10 nm) formed via in-situ synthesis route. The as-fabricated nanohybrid catalysts of Fe3O4@CFR@PdNPs and Fe3O4@CFR@GO@PdNPs with excellent dispersibility and stability are reusable after magnetically separation from catalytic systems. Especially, a super active performance was demonstrated for catalytic reduction of methylene blue dye with highest TOF (5260 min-1) yet reported in literatures using a very low dosage of Fe3O4@CFR@GO@PdNPs catalyst. In addition, the Fe3O4@CFR@GO@PdNPs catalyst also exhibits a highly catalytic efficiency for Suzuki coupling reaction using pure water as a green solvent at room temperature.