以柠檬酸、聚乙烯亚胺、硫脲为原料,通过水热法制备了绿色荧光碳量子点(GCQDs)和红色荧光碳量子点(RCQDs)。采用溶胶-凝胶法制备纳米TiO2,通过物理方法制备GCQDs/TiO2及RCQDs/TiO2二元复合光催化剂,将2种复合光催化剂与氧化石墨烯(GO)复合制备了GCQDs/TiO2/GO及RCQDs/TiO2/GO三元复合光催化剂。采用傅里叶变换红外光谱仪、X射线衍射仪、透射电子显微镜对CQDs/TiO2、CQDs/TiO2/GO进行了结构形貌表征。以次甲基蓝溶液模拟污染物,通过紫外光谱对CQDs/TiO2、CQDs/TiO2/GO的光催化降解性能进行了研究,并采用正交试验优化了三元复合光催化剂的合成条件。结果表明:光照10min条件下,GCQDs/TiO2、RCQDs/TiO2对次甲基蓝的降解率分别为72.13%、53.46%,GCQDs/TiO2/GO、RCQDs/TiO2/GO光催化性能明显优于二元复合光催化剂,降解率分别达到97.03%、99.6%。通过正交试验和单因素实验得到RCQDs/TiO2/GO最佳配比为:0.5g TiO2、0.4g RCQDs、m(GO)/m(RCQDs/TiO2)为1∶10。
Green fluorescent carbon quantum dots (GCQDs) and red fluorescent carbon quantum dots (RCQDs) were prepared by hydrothermal method using citric acid,polyethyleneimine and thiourea as raw materials.Titanium dioxide nanoparticles (TiO2) were prepared by sol-gel method,and then GCQDs/TiO2 and RCQDs/TiO2 binary composite photocatalysts were prepared by physical mixing method.Subsequently,GCQDs/TiO2/GO and RCQDs/TiO2/GO ternary composite photocatalysts were prepared by compounding the two composite photocatalysts with graphene oxide (GO).Infrared spectroscopy (FT-IR),fluorescence spectroscopy (PL) and transmission electron microscopy (TEM) were used to characterize the structure and morphology properties of CQDs/TiO2 and CQDs/TiO2/GO.The photocatalytic degradation performance of CQDs/TiO2 and CQDs/TiO2/GO was investigated by ultraviolet (UV) spectroscopy using methylene blue solution to simulate pollutants,and orthogonal experiments were used to optimize the synthesis conditions of the ternary composite photocatalysts.The experimental results showed that under the condition of 10 minutes of light irradiation,the degradation rates of methylene blue by for GCQDs/TiO2 and RCQDs/TiO2 were 72.13% and 53.46%,respectively.The photocatalytic performance of GCQDs/TiO2/GO and RCQDs/TiO2/GO was significantly better than those of the binary composite photocatalysts,achieving degradation rates of 97.03% and 99.6%,respectively.The optimal ratios of RCQDs/TiO2/GO were obtained by orthogonal and single-factor experiments as 0.5g of TiO2,0.4g of RCQDs,and the mass ratio of GO to RCQDs/TiO2 was 1∶10.
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基金资助
东营市科学发展基金项目(DJ2021021,DJ2021018,DJ2020026)
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