中孔炭负载二氧化钛光催化剂的制备及降解甲基橙

Preparation of TiO2/mesoporous carbon composites and their photocatalytic performance for methyl orange degradation

  • 摘要: 以模板法制备的中孔炭为载体,通过溶胶凝胶法制备了二氧化钛/中孔炭复合光催化剂,并考察了其对甲基橙的光催化去除能力。复合材料中二氧化钛含量及其晶型结构分别通过改变前驱体组成及煅烧温度进行调节。材料的结构性能通过氮气吸附、X射线衍射(XRD)、能谱分析仪(EDS)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、热重分析仪(TG)等测试技术进行了表征。结果表明,由于中孔炭的纳米孔限域作用,锐钛矿型的二氧化钛以纳米颗粒形式均匀分散在炭的网络骨架界面,从而形成了高度分散的二氧化钛/中孔炭纳米复合材料。另外,复合材料中的中孔吸附作用协同纳米二氧化钛的高效光催化作用,明显提高了复合材料在紫外光照射下对于水溶液中甲基橙的去除能力。在光照射下反应75min时样品对甲基橙的去除率可达89%。甲基橙光降解反应遵循一级反应动力学,其最大反应速率为0.015min-1。

     

    Abstract: Mesoporous carbon (MC) prepared using colloidal silica templates was used as a support to synthesize TiO2/MC composites using a sol-gel method. The TiO2 content and the crystalline structure of TiO2/MC photocatalysts can be tuned by the precursor composition and calcination temperature, respectively. MC and TiO2/MC composites were characterized by nitrogen adsorption, XRD, TG, SEM, TEM and electron energy dispersive spectroscopy. Results showed that the anatase TiO2 nanoparticles were highly dispersed on the surface of the carbon framework. As-prepared composites exhibited high photocatalytic activities for methyl orange (MO) degradation under UV irradiation, and a synergistic effect of adsorption and photocatalytic degradation was observed. The MO removal rate reached 89% after UV irradiation for 75 min. The kinetics of MO degradation can be well fitted with a first-order reaction model and the largest rate constant observed was 0.015 min-1.

     

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