BiVO4-TiO2光催化剂的超声辅助合成及其可见光性能

BiVO4-TiO2 Synthesized by Ultrasound Assisted Mixing for Photocatalytic Oxidation under Visible Light

中文关键词:  光催化氧化  异质结催化剂  甲醛  二氧化钛  钒酸铋

英文关键词:photocatalytic oxidation  heterojunction catalysts  formaldehyde  TiO₂  BiVO₄

中文摘要:

      光催化氧化技术已被广泛应用于气态污染物催化降解, 被普遍认为是一种高效降解室内低浓度甲醛污染的治理技术. TiO₂是应用最广泛的一种光催化剂, 具有强氧化能力、低成本、无毒等优点, 但存在仅能被紫外光激发的缺点; BiVO₄具有适宜的带隙和多样化的晶体结构, 可提升催化剂的可见光反应活性. 引入4种表面活性剂构建BiVO₄/TiO₂异质结结构, 研究考察表面活性剂种类、掺入量及混合方法等对BiVO₄-TiO₂可见光催化氧化甲醛性能的影响, 应用XRD、BET、PL、UV-Vis、XPS等分析表征技术对催化剂微观结构及性能进行表征分析. 研究结果表明, 以NaOH为表面活性剂, 采用超声辅助混合所制的BiVO₄-TiO₂催化剂性能最佳, 其48 h甲醛去除率高达97.1%, 且稳定性良好, 这均归结于高比表面积、丰富的孔径分布以及BiVO₄与TiO₂间所形成异质结结构, 提升光生载流子的分离, 降低光生电子和空穴的复合速率.

英文摘要:

      Photocatalytic oxidation technology is widely used for the catalytic degradation of gaseous pollutants and recognized as an effective treatment technology for low concentration indoor formaldehyde pollution. TiO₂, which has strong oxidation capacity, low cost and non-toxic advantages, is the most widely used photocatalyst but can only be excited by ultraviolet light. BiVO₄ has a suitable band gap energy and diversified crystal structure, which can improve the reactivity of the catalyst in visible light. In this study, four kinds of surfactants were introduced to BiVO₄ and TiO₂ for constructing the heterojunction structure, and the effects of surfactant type, incorporation, and mixing method on the formaldehyde oxidation of BiVO₄-TiO₂ were investigated. XRD, BET, PL, UV-Vis and XPS techniques were used to analyze the microstructure and performance of the catalyst. The results showed that the BiVO₄-TiO₂ catalyst prepared with NaOH as a surfactant exhibited the best performance. The 48 h formaldehyde removal rate reached 97.1%, indicating good stability. This was attributed to its high specific surface area, rich pore size distribution and heterojunction structure formed between BiVO₄ and TiO₂ that improved carrier separation efficiency while reducing electron-hole recombination rates.