Improving the photocatalytic activity and stability of graphene-like BN/AgBr composites

Graphene-like BN/AgBr hybrid materials were synthesized using the facile water bath method and characterized using X-ray diffraction (XRD), energy dispersive X-ray spectrometry (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL), Fourier transform infrared spectra (FT-IR), inductively coupled plasma optical emission spectrometry (ICP-OES) and Brunner-Emmet-Teller (BET) analysis. The photocatalytic activity of the graphene-like BN/AgBr hybrid materials was evaluated using methyl orange (MO) as a target organic pollutant. The results indicated that the photocatalytic activity of AgBr could be significantly improved by coupling with a proper amount of graphene-like BN. In addition, the optical loading amount of graphene-like BN was observed to be 1 wt%. The MO molecules can be decomposed completely within 15 min under visible light irradiation, and the photocatalyst can be reused 5 times without losing activity. The XRD pattern of the cycling sample revealed that no diffraction peaks of metallic Ag were present, which indicated that introducing a small amount of graphene-like BN can effectively suppress the reduction of silver ions. The results of the photocurrent and impedance analysis indicated that a small amount of graphene-like BN was beneficial for the separation of photogenerated electrons and holes, which could enhance the photoactivity of graphene-like BN/AgBr. Based on the experimental results, a possible visible-light photocatalytic degradation mechanism is also discussed.