多孔棒状FeVO4的制备及可见光催化性能研究

以Fe(NO₃)₃和NH₄VO₃为无机源, 氨水为pH调节剂, 采用水热法制备了多种形貌纯三斜相的多孔FeVO₄。采用X射线衍射、扫描电子显微镜和紫外-可见漫反射光谱等技术表征了样品的物理性质。结果表明, 水热温度和反应液的pH对晶相结构和粒子形貌有较大的影响: 当水热温度为180℃, 反应液的pH为4.0或7.0时, 可制得多孔三斜相FeVO₄纳米棒; 当水热温度为120℃, 反应液的pH为4.0 时制得的三斜相FeVO₄为片状结构; 而当水热温度为180℃, 反应液的pH升至10.0或水热温度变为240℃, 反应液的pH保持4.0不变时均制得含有少量FeVO₄的Fe₂O₃。在可见光照射光催化降解甲基橙的反应中, 具有最高比表面积(10.4 m²/g)的多孔棒状FeVO₄光催化活性最高, 这是因为它具有最高的结晶度、比表面积和表面氧空位密度、多孔结构和最低的带隙能。

Preparation and Visible-light-driven Photocatalytic Performance of Porous Rod-like FeVO4

Pure triclinic porous FeVO₄ with multiple morphologies were fabricated by adopting hydrothermal strategy using Fe(NO₃)₃ and NH₄VO₃ as inorganic source and NH₃ solution as pH adjuster. The samples were characterized by means of techniques such as X-ray diffraction, scanning electron microscopy, and ultraviolet-visible diffuse reflectance spectroscopy. It was found that hydrothermal temperature and pH of the precursor solution exerted a great effect on the crystalline structure and the particle morphology of the product. Porous triclinic FeVO₄ nanorods were generated hydrothermally at 180℃ and pH of 4 or 7, sheet-like FeVO₄ was obtained at pH 4.0 and hydrothermal temperature of 120℃. However, the mixture of Fe₂O₃ (in majority) and FeVO₄ (in minority) was prepared when pH of the precursor solution was raised to 10 at 180℃ or the hydrothermal temperature was raised to 240℃ at pH 4.0. Among the FeVO₄ samples, porous FeVO₄ nanorods with the highest surface area of 10.4 m²/g exhibited the best visible-light-driven photocatalytic performance for the degradation of MO. It is concluded that such an excellent photocatalytic performance is attributed to its higher crystallinity, surface area, and surface oxygen vacancy density, porous structure, and lower bandgap energy.