多孔结构Bi2WO6光催化剂的制备及其模拟燃油催化氧化脱硫活性

采用水热法合成了多孔结构Bi₂WO₆光催化剂, 借助X射线衍射(XRD)、场发射扫描电子显微镜(FESEM)、透射电子显微镜(TEM)、X射线能量色散谱(EDS)、紫外-可见漫反射(UV-Vis-DRS)、N2吸附/脱附等测试手段对样品的物相组成、形貌、比表面-孔径分布和光吸收特性等进行了表征。考察了水热温度、水热反应时间对Bi₂WO₆的形貌、比表面-孔径分布和光吸收特性影响, 并探讨了Bi₂WO₆光催化剂对模拟燃油的脱硫活性。结果表明, 在强酸性条件下水热温度和水热时间对Bi₂WO₆的形貌、比表面积和催化活性影响显著, 190℃水热反应2 h所得Bi₂WO₆为新颖的鸟巢状微晶, 且鸟巢状Bi₂WO₆由片层状二级结构组装而成。XRD和EDS表明, 鸟巢状结构的Bi₂WO₆为正交晶系, 纯度较高。N₂吸附-脱附测试结果表明, 鸟巢状Bi₂WO₆具有多孔结构, 孔主要分布在10 nm, 比表面积大约为17.49 m²/g。催化活性测试结果表明, 三维介孔结构Bi₂WO₆具有较好的模拟燃油脱硫效果, 在空气流量为100 mL/min, 催化剂加入量为1.2 g/L, 可见光照射180 min, 模拟汽油脱硫率高达91.2%, 且催化剂的稳定性能较好。

Synthesis of Porous-Bi2WO6 and Its Photocatalytic Oxidative Desulfurization (Photo-ODS) Activity of Simulation Fuel

Porous-Bi₂WO₆ was synthesized by a hydrothermal process. The phase composition, morphology, surface area/pore size distribution and optical properties of as-synthesized Bi₂WO₆ sample were investigated by X-ray diffraction (XRD), filed-scanning electron microscope (FE-SEM), transmission electron mcroscope (TEM), energy dispersive spectrometer (EDS), UV-Vis absorption spectrum (UV-Vis-DRS), and low-temperature N₂ adsorption/desorption techniques. Furthermore, the photocatalytic oxidative desulfurization (Photo-ODS) activity of as-synthesized Bi₂WO₆ samples was also investigated. The experimental results reveal that reaction temperature and reaction time have a significant effect on the morphology and structure of Bi₂WO₆ under the strong acidic medium. After 2 h of reaction at 190℃, the as-obtained sample exhibits a novel nest-like 3D Bi₂WO₆ microcrystal with scales of 3-4 μm. HR-SEM reveals that the 3D nest-like Bi₂WO₆ microcrystal composes of many small secondary nanoplates. XRD and EDS results confirm that the as-synthesized D nest-like Bi₂WO₆ microcrystal is orthorhombic pure-Bi₂WO₆. N₂ adsorption/desorption isotherms and the pore distribution result show that nest-like 3D Bi₂WO₆ microcrystal has pores in the size of 6-8 nm and the BET surface area is calculated to be as much as 17.49 m²/g. The photocatalytic experimental result illustrates that as-synthesized 3D nest-like porous Bi₂WO₆ microcrystals exhibit an excellent photocatalytic performance to photocatalytic oxidative desulfurization for simulated fuel oil under sun-like light irradiation. Under the conditions of 100 mL/min air flow, 1.2 g/L photocatalyst amount, and visible-light irradiation for 180 min, the desulfurization rate of simulated fuel oil reaches 91.2%, and the stability of photoctalyst is also good.