石墨烯–铁酸铋纳米晶复合材料的制备及其催化性能研究

Preparation and Catalytic Properties of Graphene-Bismuth Ferrite Nanocrystal Nanocomposite

BiFeO_(3)(BFO)是一种新型可回收光响应催化剂,但较高的光生电子/空穴对复合率和较低的量子产率限制了其实际应用。本研究通过水热法制备出还原氧化石墨烯-BFO(RGO-BFO)纳米晶复合材料,表征与测试结果表明,相比于BFO颗粒,复合材料的禁带宽度E_(g)为2.0 e V,降低约10%;40 min对亚甲基蓝吸附–催化效率接近100%,远高于BFO颗粒(28%),这主要由于复合体系中光生电子/空穴对复合率更低。通过本征磁性回收并重复利用6次后,复合材料仍保持89.1%催化效率,表现出优异催化性能。

BiFeO_(3)(BFO)is a novel recyclable photocatalyst which benefits from its appropriate theoretical band gap and room temperature ferromagnetism,yet the relatively high recombination rate of photogenerated electron-hole pairs and low quantum yield limit its practical catalytic performance.Here,a composite material of reduced graphene oxide and BiFeO_(3)nanocrystals(RGO-BFO)was successfully prepared via a hydrothermal self-assembly process with about 10 wt%RGO loaded 85 wt%BFO nanocrystalline(~10 nm).Specific surface area of the composite is about 5 times of that of pure BFO particles.Furthermore,this nanocomposite demonstrates the enhanced ultraviolet absorption behavior as well as its intrinsic visible light absorption,with an energy gap(E_(g))of 2.0 eV,which is about 10%lower than BFO particles(2.3 eV).As a result,a significantly higher catalytic efficiency of nearly 100%of the RGO-BFO was obtained as compared to the 25%value of BFO after a 40-min process of adsorption and photodegradation for methylene blue.The improved performances may be attributed to the additional photogenerated electron-hole pairs and lower recombination ratio,which can be proved by the result of photoelectric response.As an intrinsically ferromagnetic material,it could be easily recycled from the solventsystem,and its repetitive catalytic efficiency maintained 89.1%after 6 cycles,showing a good catalytic stability.