光催化材料Bi4O7/BiOBr的制备及其光催化性能研究

以自制的铋酸钾（KBiO₃）为前驱物,采用低温水热法制备七氧化四铋（Bi₄O₇）,再利用氢溴酸原位离子刻蚀法首次成功制备了Bi₄O₇/BiOBr复合物。通过X射线衍射（XRD）和扫描电子显微镜（SEM）分别观测了样品的物相和形貌特征,复合相具有比二者单相更佳的可见光降解罗丹明B（RhB）的性能,最高可达到30 min内降解86.9%;紫外可见漫反射光谱（DRS）和光致发光光谱（PL）分别证明了其性能的提升是由于复合相拥有更广的光学响应范围和更低的光生载流子复合效率。超氧自由基和空穴是该体系光催化降解过程中的活性物质,并由此提出了一种可能的光催化降解机制,且复合相比单相Bi₄O₇具有更好的光催化降解稳定性。

Preparation of photocatalytic materials of Bi4O7/BiOBr and study on their photocatalytic performance

Bismuth tetroxide（Bi₄O₇） was prepared by low temperature hydrothermal method using homemade potassium bismuth oxide（KBiO₃） as precursor and Bi₄O₇/BiOBr composite was successfully prepared by in-situ ion etching with hydrobromic acid.The phase and morphology characteristics of the samples were observed by x-ray diffraction（XRD） and scanning electron microscope（SEM）,respectively.The composite phase had better visible light degradation performance of Rhodamine B（RhB）than the single phase,which could reach 86.9% degradation in 30 min at most.Ultraviolet-visible diffuse reflectance spectroscopy（DRS） and Photoluminescence spectroscopy（PL） respectively proved that the improvement of the performance was due to the wider optical response range and lower photogenerated carrier recombination efficiency of the composite phase.·O ^2-and h ⁺ were the active substances in the photocatalytic degradation process of the system.According to this,a possible photocatalytic degradation mechanism was proposed.The composite phase had better photocatalytic degradation stability than the singlephase Bi₄O₇.