A highly selective conversion of toxic nitrobenzene to nontoxic aminobenzene by Cu2O/Bi/Bi2MoO6

Abstract

Cu₂O/Bi/Bi₂MoO₆, a ternary catalyst, was expertly prepared using an in situ catalytic reduction reaction. All synthetic materials were carefully researched by high-resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible diffuse reflection spectra (UV-vis DRS). The elemental Bi was generated from Bi₂MoO₆ (BM) after a circular reduction catalysis process of 4-nitrophenol (4-NP) and evenly dispersed in the surface of the leaves of BM flower-like spheres, which was simultaneously coated with Cu₂O. The multiphase samples achieved highly effective catalytic activity (10 053.6 min⁻¹ g⁻¹) for the conversion of the highly toxic 4-NP to the less toxic aminobenzene, compared to the single phase Cu₂O and BM nanoparticles. Moreover, the excellent reusable stability of the compositing samples was confirmed by executing successive recycling experiments. It was proposed that the Bi³⁺/Bi⁰ pairs were the key active species which were produced via prompt reduction and oxidation with the help of Cu₂O. The active interfacial contact between copper oxide/metallic Bi/BM (Cu₂O/Bi/BM) in the designed sandwich structure facilitated the production and maintained the balance of Bi³⁺/Bi⁰ pairs, contributing to the enhanced activity and excellent stability.