论文部分内容阅读
利用普鲁士蓝(PB)作为γ-Fe2O3前驱体,先依次在氧化石墨烯(GO)片上负载PB和CdS纳米粒子,再将其置于惰性气体(N2)氛围下进行煅烧,成功制备出CdS/RGO/γ-Fe2O3三元复合光催化剂.通过改变PB负载量可以得到不同γ-Fe2O3含量的三元光催化剂,且PB的方块状形貌在煅烧后得以保持.利用XRD、EDS、TEM、FT-IR、UV-vis等手段对所制备的样品进行组成、结构、形貌、光吸收等的分析表征,并以罗丹明B (RhB)为模拟污染物研究上述催化剂对有机污染物的光催化降解性能.与二元复合物CdS/RGO相比,三元CdS/RGO/γ-Fe2O3光催化剂表现出更强的可见光催化活性,这说明γ-Fe2O3在光催化过程中起了重要作用.而且,由于γ-Fe2O3具有铁磁性,在外加磁场的作用下可以将光催化剂从反应体系中快速分离回收.同时,还研究了CdS/RGO/γ-Fe2O3光催化剂的降解动力学过程,并通过光催化剂的荧光表征和活性基团捕获实验,提出了光催化降解的机理.“,”With Prussian blue (PB) as the precursor for γ-Fe2O3,the tri-component CdS/RGO/γ-Fe2O3 photocatalyst was prepared through loading PB nanocubes and CdS nanoparticles on graphene oxide (GO) nanosheets,followed by a calcination process in inert atmosphere (N2).The content of γ-Fe2O3 in the CdS/RGO/γ-Fe2O3 photocatalyst can be adjusted by changing the loading amount of PB,and the cubic morphology of PB was maintained after the calcination.The composition,structure,morphology and light absorption of the as-prepared products were investigated by X-ray diffraction (XRD),X-ray energy dispersive spectroscopy (EDS),field emission scanning electron microscopy (SEM),transmission electron microscopy (TEM),infrared spectroscopy (FT-IR),Raman spectroscopy and ultraviolet-visible (UV-vis) spectroscopy.The photocatalytic activity of the ternary photocatalysts was evaluated by the degradation of the organic pollutant of Rhodamine B (RhB) under visible-light irradiation.It was found that the degradation process of RhB follows pseudo-first-order kinetics.Compared to the bi-component CdS/RGO photocatalyst,the tri-component CdS/RGO/γ-Fe2O3 exhibited greatly enhanced photocatalytic activity,demonstrating that the γ-Fe2O3 played an important role in the photocatalytic process.The CdS/RGO/γ-Fe2O3 composite with PB loading amount of 12 mg exhibits the highest photocatalytic degradation efficiency of about 99.8％ and the highest apparent reaction rate constant (k) value of about 0.03289 min-1,which is almost 2.9 times and 1.8 times higher than that of CdS and CdS/RGO,respectively.This result indicates that a suitable loading amount of γ-Fe2O3 is important to optimize the photocatalytic performance of the CdS/RGO/γ-Fe2O3 composites.Moreover,owing to the ferromagnetism of γ-Fe2O3,the CdS/RGO/γ-Fe2O3 photocatalyst could be easily separated from the reaction solution for recycling by a magnet.A possible photocatalytic mechanism was also proposed based on the photoluminescence (PL) characterization and the active species capture experiment.It was demonstrated that the enhanced photocatalytic degradation properties of CdS/RGO/γ-Fe2O3 composites can be ascribed to the excellent conductivity of RGO and the construction of Z-scheme heterostructure between CdS and γ-Fe2O3,which facilitate the transport and separation of photogenerated carriers.