Novel 3D flowerlike Au/BiOBr0.2I0.8 composites with highly enhanced visible-light photocatalytic performances

Abstract

A series of 3D flowerlike Au/BiOBr0.2I0.8 composites with different Au contents have been synthesized by a hydrothermal combinated with photodeposition method. The as-prepared samples were characterized by power X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), high-resolution transmission electron micrographs (HRTEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectra (DRS), and photoluminescence (PL) emission spectroscopy. The photocatalytic activities of these Au/BiOBr0.2I0.8 composites under visible-light irradiation (λ>420nm) were evaluated by the degradation of methyl orange (MO), rhodamine B (RhB) and phenol. The results revealed that the Au/BiOBr0.2I0.8 composites exhibited much higher photocatalytic activities than pure BiOBr0.2I0.8. And the 0.6%Au/BiOBr0.2I0.8 sample exhibited the highest photocatalytic activity. The enhanced photocatalytic activity could be attributed to Au deposits by acting as electron traps and the surface plasma resonance effect of Au. A possible photocatalytic mechanism of Au/BiOBr0.2I0.8 composites was also proposed.