Au@FeO@PANI hybrid shells with controllable polyaniline (PANI) coatings as advanced supported catalysts have been fabricated. Specifically, FeO and Au nanoparticles were assembled on SiO templates, followed by conducting polymer PANI coating, leading to the formation of Au@FeO@PANI hybrid shells after the template removal. The resultant supported Au nanocatalysts not only maintain hollow structures but also possess high saturation magnetization (65.46 emu/g). Catalytic tests toward the reduction of 4-nitrophenol in the presence of NaBH indicate that PANI and FeO not only endow high stability and recyclability but also can largely improve the catalytic activity of Au nanoparticles because of their synergetic effects. It is believed that FeO@PANI hybrid shells can be regarded as multifunctional supports for noble metal nanocatalysts with a remarkably improved catalytic performance.

Fe3O4/PANI/Au/m-SiO2 hybrid catalysts have been demonstrated that have high stability and recyclability in liquid phase reactions.

Hydrophilic Fe3O4-Au Janus nanoparticles have been synthesized through a facile aqueous solution-based Fe3O4 seed-mediated chemical reduction route, where Au nanoparticles can be in situ formed on surfaces of PVP-modified Fe3O4 nanoparticles by adopting the well-known citrate reduction route. The diameter of Au nanoparticles can be controllably tuned in the range of 3-12 nm by simply changing the initial molar ratio between sodium citrate and auric acid. The as-fabricated hydrophilic Fe3O4-Au Janus nanoparticles have shown excellent catalytic performance with high catalytic activity and recyclability due to the synergetic effect between Au and Fe3O4 nanoparticles.

Multifunctional nanocatalysts of Au@FeO/m-SiO yolk@shell hybrids had been developed through a template-assisted synthesis, where FeO nanoparticles (∼12 nm) and m-SiO shells were sequentially assembled on surfaces of Au/SiO core/shell templates, followed by selective etching of the inner SiO cores, leading to the formation of Au@FeO/m-SiO yolk@shell hybrids. The FeO nanoparticles were implanted in the inner surfaces of m-SiO shells with partially exposed surfaces to the inner cavity. The novel design not only ensures a high surface area (540.0 m/g) and saturation magnetization (48.6 emu/g) of the hybrids but also enables interaction between Au and FeO nanoparticles. Catalytic tests toward the reduction of 4-nitrophenol in the presence of NaBH indicated that Au@FeO/m-SiO yolk@shell nanocatalysts not only showed high stability and recyclability but also maintained improved catalytic activity as a result of the synergetic effect resulting from Au and FeO interactions.