One-step combustion synthesis of β-Bi2O3-NiO/Ni composites and their visible light photocatalytic performance

A series of novel β-Bi2O3-NiO/Ni heterojunctions were synthesized via one-step solution combustion method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis spectroscopy and terephthalic acid (TA) fluorescence. The obtained NiO/Ni samples showed visible light absorbance ability and had narrow band gap of ca. 2.20 eV. The coupling of β-Bi2O3 with NiO/Ni promoted the visible light catalytic performance. The enhanced activity could be ascribed to the increase of separation efficiency of electrons and holes and the existence of metallic Ni, which might show a plasmonic effect and could increase the light absorption ability. The scavengers’ tests demonstrated that hydroxyl radical and holes species played a major role for the methyl orange degradation. Furthermore, the as-obtained samples had magnetic properties and could be recycled easily by magnetic separation from the reaction system. Finally, the mechanism of the photocatalytic reaction over β-Bi2O3-NiO/Ni composites was proposed.