Fabrication and characterization of core-shell polystyrene/polyaniline/Au composites and their catalytic properties for the reduction of 4-nitrophenol

- Core-shell PS/PANI/Au composites were prepared by a novel method with the help of the electrostatic attraction between Au(en)23+ and −SO3−.
- The core-shell PS/PANI/Au composites performed high efficiency in catalytic reduction of 4-nitrophenol to corresponding 4-aminophenol with NaBH4 as reducing agent.
- The reaction rate constants were calculated through the pseudo-first-order kinetic equation, which were comparable with that of Au catalyst in the literature.

Herein, polystyrene/polyaniline/Au (PS/PANI/Au) composites were prepared by a novel method using self-made Au(en)2Cl3 as the Au source and were used as the catalysts for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). Before the preparation of PS/PANI/Au, PS microparticles were sulfonated by the copolymerization between styrene and sodium 4-styrenesulfonate (SSS). Then self-made Au(en)2Cl3 was added and Au(en)23+ species were adsorbed on the surface of sulfonated PS particles due to the electrostatic attraction. The Au(en)23+ was then reduced to Au nanoparticles in situ by aniline monomer. After the polymerization of the residual aniline monomer by ammonium persulfate (APS), the PS/PANI/Au composite catalysts were obtained. The morphology and structure of the as-prepared PS/PANI/Au composites were characterized by TEM, FT-IR, XPS and EDX. Their catalytic performance for the reduction of 4-NP by NaBH4 was evaluated by means of UV-vis spectroscopy. The as-prepared PS/PANI/Au composites are very active for the reduction of 4-NP by virtue of the interaction between Au nanoparticles and PANI shell. The catalytic reaction obeys the pseudo-first-order reaction equations and the reaction rate constants are also calculated in this paper.

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