Rod-like β-FeOOH@poly(dopamine)–Au–poly(dopamine) nanocatalysts with improved recyclable activities

A novel rod-like β-FeOOH@poly(dopamine)-Au-poly(dopamine) nanocomposite is developed for recyclable catalysis. Firstly, the rod-like β-FeOOH template was coated in situ by a layer of poly(dopamine) (PDA) to form a core/shell nanostructure. Then the negatively charged Au nanocatalysts were well-immobilized onto the periphery of the β-FeOOH@PDA nanorod. To protect the Au nanocrystals from leaching during the catalytic reactions, another PDA layer was coated onto the above particles to form a sandwich-like PDA-Au-PDA shell on the β-FeOOH rod core. The reduction of Rhodamine B (RhB) was introduced as a model reaction to evaluate the catalytic activity of the as-prepared nanocomposites. It was found that the catalytic rate sharply increased with an increasing amount of the nanocatalyst. Benefitting from the thin outer layer of PDA, the recyclability of the nanocatalyst dramatically increased. After five times of catalytic reaction, the activity was maintained as high as 98.3%, while the β-FeOOH@PDA-Au showed it to be retained at only 73.4%.