Enhanced photocatalytic degradation for organic pollutants by a novel m-Bi2O4/Bi2O2CO3 photocatalyst under visible light

To heighten the absorption to visible light and improve photocatalytic degradation to organic pollutants, a novel photocatalyst of m-Bi2O4/Bi2O2CO3 was constructed through a facile hydrothermal method. The crystal structure, optical properties, morphology, composition and photocatalytic ability of the photocatalysts were characterized via X-ray diffraction, Fourier transform infrared spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy, field emission scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscope (TEM), high resolution TEM, selected-area electron diffraction and X-ray photoelectron spectroscopy technologies. The as-prepared photocatalysts could efficiently degrade rhodamine B and mixed dye under visible light. The removal rate was up to 95.3% within 50 min. The results demonstrated that m-Bi2O4/Bi2O2CO3 photocatalysts showed outstanding photocatalytic degradation ability compared to the single photocatalyst with the narrow band gap. In addition, photocurrent response tests certified that the heterostructure of the photocatalysts effectively accelerated the separation and migration of photo-induced electrons and holes. Active species trapping experiments indicated that holes (h+) and superoxide radical (•O2−) were major species rather than hydroxyl radicals (•OH) during the degradation process of organics. According to the test results, a probable photocatalytic mechanism was proposed. This work provided a new and efficient photocatalyst for environmental remediation and water treatment.