五味子植物合成Z型g-C_(3)N_(4)/BiVO_(4)及光催化降解性能研究

Synthesis of Z-scheme g-C_3N_4/BiVO_(4) from Schisandra chinensis and its Photocatalytic Degradation Performance

Z-型异质结光催化纳米材料因其高效的催化性能而备受关注。植物提取物作为绿色、可持续的介质,在纳米材料的合成中起到了溶剂和结构诱导剂的作用。研究中以五味子水提物为络合剂,首先通过简单的水热法制备了BiVO_(4),然后采用煅烧法制备了不同掺杂比率的BiVO_(4)/g-C_(3)N_(4)异质结光催化剂。利用X射线衍射、傅里叶变换红外光谱、X射线光电子能谱,紫外-可见漫反射光谱、扫描电子显微镜、透射电子显微镜对其微观形态、晶体结构、物理化学性质和光学性质进行了表征。以诺氟沙星为目标,考察样品在可见光下光催化降解性能。结果表明:BiVO_(4)/g-C_(3)N_(4)具有更高的界面电荷转移效率和更宽的可见光响应范围,当g-C_(3)N_(4)的掺杂率为10%时光降解活性最佳,120 min内实现对诺氟沙星85.6%的降解率。自由基捕获实验和能带分析结果证实:BiVO_(4)/g-C_(3)N_(4)体系中形成了Z型电子转移机制,·OH和·O^(2-)在降解过程中发挥了重要作用。

Z-scheme heterojunction photocatalytic nanomaterials have attracted much attention because of their efficient catalytic performance.As a green and sustainable medium,plant extracts play the role of solvent and structure inducer in the synthesis of nanomaterials.In this work,a novel BiVO_(4) was prepared by a simple hydrothermal method using aqueous extract of Schisandra chinensis as the complexing agent,and then BiVO_(4)/g-C_(3)N_(4) heterojunction photocatalysts with different doping ratios were prepared by calcination method.The microscopic morphology,crystal structure,physicochemical and optical properties were characterized by X-ray diffraction,Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,UV-vis diffuse reflectance spectroscopy,scanning electron microscopy and transmission electron microscopy.The photocatalytic degradation performance of the samples under visible light was investigated with norfloxacin as the target.The results showed that BiVO_(4)/g-C_(3)N_(4) had higher interfacial charge transfer efficiency and wider visible light response range,and the best photodegradation activity was achieved when the doping rate of g-C_(3)N_(4) was 10%,and the degradation rate of 85.6%for norfloxacin was achieved within 120 min.The results of radical trapping experiments and energy band analysis confirmed that a Z-scheme electron transfer mechanism was formed in the BiVO_(4)/g-C_(3)N_(4) system,and·OH and·O_(2)-played an important role in the degradation process.