Ce0.67Zr0.33O2对CH4燃烧催化剂Fe2O3/Al2O3的改性作用

固定n(Ce)/n(Zr)比为0.67/0.33,用共沉淀法制得一系列CeO2-ZrO2-Al2O3固溶体.采用这些固溶体作载体,以Fe2O3为活性组分,用浸渍法制备了一系列催化剂.BET结果显示,将适量Ce0.67Zr0.33O2引入到Al2O3载体中有助于催化剂保持较高的比表面积.TPR结果显示,载体中引入适量的Ce0.67Zr0.33O2可以改善催化剂的氧化还原性能.XRD结果表明,Fe2O3在CeO2-ZrO2-Al2O3载体上呈现出良好的分散状况,老化前后催化剂的晶相结构基本无明显变化.特别是当载体中m(Ce0.67Zr0.33O2)∶m(Al2O3)的值为1∶2时,Fe2O3/CeO2-ZrO2-Al2O3催化剂在甲烷催化燃烧中显示出最佳的催化性能和抗高温老化性能.

Synthesis of Nanocrystalline Titania and Photocatalytic Degradation of Phthalate Esters

Rutile titania with different shapes(shuttle-like, sphere with needles, uniform particles) was prepared by manipulative hydrolysis of TiCl_4 in aqueous solution with a high acidity in the absence or presence of PEG-1000. The products were characterized by means of XRD, TEM and UV-Vis. As a result, shuttle-like nanocrystalline appeared and the aggregation was improved with the increase of the amount of acid and the decrease of the concentration of TiCl_4 in the absence of PEG-1000. Uniform nanoparticles were obtained in the presence of PEG-1000, and the diameter of the particles decreased with increasing the amount of PEG-1000. The photocatalyzed degradation of phthalate esters in aqueous suspensions of titanium dioxide shows that the synthesized titania has a high photocatalytic activity. The degradation products were analyzed by GC-MS technique and probable pathways for the degradation of PEs were proposed.