摘要
采用溶剂热法和煅烧法分别制备了Bi3O4Br、Bi12O17Br2和Bi24O31Br10三种不同的富铋型溴氧铋材料。利用X射线粉末衍射(XRD)和扫描电子显微镜(SEM)对不同材料的物相组成与形貌进行了表征。在模拟太阳光下分别测试了三种富铋型溴氧铋材料的光催化苯甲醇选择性氧化性能。其中,Bi24O31Br10样品具有最佳的光催化性能,光照2小时后,苯甲醇的转化率为22.3%,苯甲醛的选择性可达100%。通过捕获剂实验、电子顺磁共振波谱(EPR)和紫外–可见漫反射光谱(DRS)对不同材料表现出不同光催化活性的原因进行了分析。结果表明,三种不同的富铋型溴氧铋材料光催化氧化苯甲醇的主要活性物种均为光生空穴(h+)和超氧自由基(·O2-)。Bi24O31Br10具有最佳光催化活性可能归因于Bi24O31Br10产生·O2-的能力强于Bi3O4Br和Bi12O17Br2。此外,Bi24O31Br10的价带电位更正,光生h+的氧化性更强,有利于苯甲醇的氧化。
Three kinds of bismuth-richbismuth oxybromide materials (Bi3O4Br, Bi12O17Br2 and Bi24O31Br10) were prepared by solvothermal and calcination method, respectively. The phase compositions and morphologies of different materials were characterized by powder X-ray diffraction (XRD) and scanning electron microscope (SEM). The photocatalytic performance of different materials for the selective oxidation of benzyl alcohol was evaluated under simulated sunlight irradiation. Among them, Bi24O31Br10 sample displayed the best photocatalytic performance. After 2 hours of illumination, the conversion of benzyl alcohol was 22.3%, and the selectivity of benzaldehyde reached 100%. Subsequently, the capturing agent experiment, electron paramagnetic resonance spectra (EPR) and ultraviolet-visible diffuse reflectance spectra (DRS) were used to analyze the reasons. The results showed that the main active species were photogenerated holes (h+) and su-peroxide radicals (·O2-) for the photocatalytic oxidation of benzyl alcohol over the three materials. Bi24O31Br10 exhibited the best photocatalytic performance might be attributed to the ·O2- production ability of Bi24O31Br10 which was stronger than that of Bi3O4Br and Bi12O17Br2. In addition, the valence band potential of Bi24O31Br10 was more positive than that of Bi3O4Br and Bi12O17Br2 leading to the stronger oxidation ability of photogenerated h+, which was beneficial for the oxidation of benzyl alcohol.
出处
《材料科学》
CAS
2021年第5期545-553,共9页
Material Sciences
