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

Magnetic FeO@catechol-formaldehyde resin (CFR) core-shell nanospheres were fabricated via a controllable hydrothermal method. The shell thickness of FeO@CFR nanospheres can be effectively regulated in the range of 10-170 nm via adjusting reaction parameters. In particular, 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 FeO@CFR spheres. The obtained FeO@CFR and FeO@CFR@GO nanospheres can be used as the effective catalyst supports of small Pd nanoparticles (PdNPs, <10 nm) formed via an in situ synthesis route. The as-fabricated nanohybrid catalysts of FeO@CFR@PdNPs and FeO@CFR@GO@PdNPs with excellent dispersibility and stability are reusable after magnetic separation from catalytic systems. In particular, a super active performance was demonstrated for the catalytic reduction of methylene blue dye with highest turnover frequency (5260 min) yet reported in the literature using a very low dosage of the FeO@CFR@GO@PdNP catalyst. In addition, the FeO@CFR@GO@PdNP catalyst also exhibits a highly catalytic efficiency for the Suzuki coupling reaction using pure water as a green solvent at room temperature.