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利用水热法合成了一维棒状BiPO_4微晶,在此基础上采用浸渍一焙烧法进行g-C_3N_4量子点表面修饰获得新颖的g-C_3N_4/BiPO_4异质结。借助X射线衍射(XRD)、场发射扫描电镜(PE-SEM)、透射电镜(HRTEM)、能谱(EDS)、紫外-可见漫反射(UV-VisDRS)等测试手段对所得样品的相组成、形貌和谱学特征进行了表征。选择罗丹明B(RhB)和苯酚作为模型污染物研究了所得在可见光下的催化活性。结果表明,样品16%(ω/ωg-C_3N_4BiPO_4对RhB降解的速率常数分別是纯g-C_3N_4和BiPO_4的4.6倍和15倍。g-C_3N_4量子点与BiPO_4之间形成异质结,抑制了光生电子-空穴对的复合,从而提高了催化剂的活性。自由基捕获实验进一步表明,超氧负离子自由基(·O_2~-)是催化降解RhB和苯酚的主要活性物种。
One-dimensional rod-shaped BiPO 4 microcrystals were synthesized by hydrothermal method. On this basis, a novel g-C 3 N 4 / BiPO 4 heterojunction was obtained by surface modification of g-C 3 N 4 quantum dots by impregnation-roasting method. The phase composition, surface area and surface morphology of the obtained samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (PE-SEM), transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS) and UV-VisDRS. Morphology and spectral features were characterized. The resulting rhodamine B (RhB) and phenol were chosen as model contaminants to study the catalytic activity under visible light. The results showed that the rate constants of 16% (ω / ωg-C_3N_4BiPO_4) degradation of RhB were 4.6 times and 15 times that of pure g-C_3N_4 and BiPO_4, respectively, and formed a heterojunction between g-C_3N_4 quantum dots and BiPO_4, Electron-hole pair recombination, thereby increasing the activity of the catalyst.Free radical trapping experiments further showed that superoxide anion radical (· O_2 ~ -) is the main active species for the catalytic degradation of RhB and phenol.