In situ preparation of novel p-n junction photocatalyst BiOI/(BiO)2CO3 with enhanced visible light photocatalytic activity

Abstract

Novel p–n junction photocatalysts BiOI/(BiO)2CO3 with different contents of BiOI were in situ synthesized by etching (BiO)2CO3 precursor with hydroiodic acid (HI) solution. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectrometry (FT-IR), energy-dispersive spectroscopy (EDS) and UV–vis diffuse reflectance spectroscopy (DRS) were employed to study the structures, morphologies and optical properties of the as-prepared samples. Under visible light (λ > 420 nm), BiOI/(BiO)2CO3 hybrid displayed much higher photocatalytic activity than pure (BiO)2CO3 and BiOI for the degradation of methyl orange (MO). The increased photocatalytic activity of BiOI/(BiO)2CO3 could be attributed to the formation of the p–n junction between p-BiOI and n-(BiO)2CO3, which effectively suppresses the recombination of photoinduced electron–hole pairs. Moreover, the tests of radical scavengers confirmed that radical dotO2− and h+ were the main reactive species for the degradation of MO.