异质结型SnO2-TiO2纳米纤维光催化降解柴油机多环芳烃

采用同轴静电纺丝法制备了SnO_2-TiO_2纳米纤维,用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、红外光谱仪(FTIR)和紫外-可见光谱能谱仪(UV-Vis),表征了SnO_2-TiO_2纳米纤维相组成和微观形貌,评价了催化剂表面化学形态和吸光特性,研究了SnO_2含量、光源条件、温度和催化稳定性对降解萘污染物的影响规律.结果表明,催化剂Sn25对萘降解效率最高.在暗光、可见光和紫外光条件下,萘降解效率分别为13.8%、37%和98%.Sn25对萘降解稳定率(标准差率)为0.36%.利用催化剂Sn25对柴油机尾气中多环芳烃(PAHs)排放污染物光催化降解应用发现,Sn25对低苯环PAHs、中苯环PAHs和高苯环PAHs的平均催化降解效率分别为80.2%、75.4%和60.2%.表明SnO_2-TiO_2纳米纤维具有较强光催化降解多环芳烃污染物能力.

Photocatalytic degradation of polycyclic aromatic hydrocarbons in diesel engine by heterojunction SnO2-TiO2 composite nanofibers

SnO₂-TiO₂ composite nanofibers were prepared by the coaxial electrospinning method. The crystalline phase and microstructure of SnO₂-TiO₂ catalysts were displayed by X-ray diffraction (XRD) and scanning electron microscope (SEM). Absorption characteristics and electrochemical properties of SnO₂-TiO₂ catalysts were characterized by X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible spectrometry (UV-Vis). The corresponding influence factors on SnO₂ content, light condition, temperature and repeated performance were analyzed of Naphthalene degradation rate. The test results showed that when SnO₂ content was 25%, Naphthalene degradation rate was the highest. Naphthalene degradation rates were 13.8% and 37% respectively in dark and visible light conditions, and it was about 98% in UV-light condition. Naphthalene degradation stability was 0.36%. Polycyclic aromatic hydrocarbons (PAHs) of low benzene ring, central benzene ring and high benzene ring were reduced by catalyst sample (Sn25) in diesel engine exhaust emission, with the degradation rates of 80.2%, 75.4% and 60.2%, respectively. Therefore, it is verified that SnO₂-TiO₂ catalyst had better photocatalytic activity in reducing PAHs emissions from diesel engine exhaust.