A simple way to prepare Au@polypyrrole/Fe₃O₄ hollow capsules with high stability and their application in catalytic reduction of methylene blue dye

Abstract

Metal nanoparticles are promising catalysts for dye degradation in treating wastewater despite the challenges of recycling and stability. In this study, we have introduced a simple way to prepare Au@polypyrrole (PPy)/Fe3O4 catalysts with Au nanoparticles embedded in a PPy/Fe3O4 capsule shell. The PPy/Fe3O4 capsule shell used as a support was constructed in one-step, which not only dramatically simplified the preparation process, but also easily controlled the magnetic properties of the catalysts through adjusting the dosage of FeCl2·4H2O. The component Au nanoparticles could catalyze the reduction of methylene blue dye with NaBH4 as a reducing agent and the reaction rate constant was calculated through the pseudo-first-order reaction equation. The Fe3O4 nanoparticles permitted quick recycling of the catalysts with a magnet due to their room-temperature superparamagnetic properties; therefore, the catalysts exhibited good reusability. In addition to catalytic activity and reusability, stability is also an important property for catalysts. Because both Au and Fe3O4 nanoparticles were wrapped in the PPy shell, compared with precursor polystyrene/Au composites and bare Fe3O4 nanoparticles, the stability of Au@PPy/Fe3O4 hollow capsules was greatly enhanced. Since the current method is simple and flexible to create recyclable catalysts with high stability, it would promote the practicability of metal nanoparticle catalysts in industrial polluted water treatment.

A simple way to prepare Pd/Fe3O4/polypyrrole hollow capsules and their applications in catalysis

“…Once NH 3 ·H 2 O was introduced into the reaction system, the alkalinity of mixture increased, which resulted in the hydrolysis of both Fe 3+ and Fe 2+ ions. Therefore, Fe(OH) 3 and Fe(OH) 2 were produced under alkaline condition, and finally Fe 3 O 4 nanoparticles formed through dehydration [18]. The as-prepared Pd nanoparticles is nearly three times larger than that of Pd nanoparticles.…”

“…This traditional preparation procedure was too complex and time-wasting, which was not beneficial for industrial production. In our previous study [18], preparation of magnetic nanoparticles and construction of PPy shell were successfully finished in one-step; however, it still acquired extra procedures to synthesize metal nanoparticles and assemble them on the surface of hard-template. Therefore, To further simplify the experimental process, and prepare magnetic hollow capsules with good catalytic activity and high stability by a simpler approach still remained a grand challenge.…”

Silk-regulated hierarchical hollow magnetite/carbon nanocomposite spheroids for lithium-ion battery anodes

“…However, it remains a challenge to develop a simple, green and reliable method for the formation of such hierarchical nanostructures. Most template-assisted methods for the formation of hollow structures involve complicated procedures including the preparation and removal of templates [24, 25]. Furthermore, the production of Fe 3 O 4 /carbon composite materials requires a complicated process.…”

Mussel inspired green synthesis of silver nanoparticles-decorated halloysite nanotube using dopamine: characterization and evaluation of its catalytic activity

“…Representative time-dependent UV-vis spectra of MB degradation in the presence of NaBH 4 by nanocomposite Patel et al 2007;Yao et al 2014). The distinguished catalytic activity towards MB reduction may be due to electrostatic interaction between positively charge MB molecules and negatively charged PDA molecules resulting in rapid deposition of MB molecules on the surface of the catalytic surface (Ma et al 2015).…”