高分散Ce-VOX/TiO_(2)均苯四甲酸二酐催化剂研究

Highly Dispersed Ce-VOX/TiO_(2)Catalyst for Gas-Phase Oxidation of Durene to Pyromellitic Dianhydride

采用浸渍法制备了不同Ce元素物质的量比的Ce-VO/TiO_(2)催化剂,考察了催化剂在均四甲苯气相氧化制均苯四甲酸二酐反应中的催化性能,通过X射线衍射(XRD)、拉曼光谱(Raman)、X射线光电子能谱(XPS)、红外光谱(FT-IR)和氢气程序升温还原(H_(2)-TPR)对催化剂进行表征。实验结果表明:催化剂活性组分呈高度分散态,Ce元素的添加增加了催化剂表面的氧缺陷和吸附氧,提高了催化剂的催化活性,且未改变TiO_(2)表面VO的存在形态。催化剂活性组分V与Ce物质的量比为1:0.1时,催化性能最佳,均苯四甲酸二酐收率达82.1%(质量分数)。

Ce-VO/TiO_(2)catalysts with different molar ratios of cerium were prepared by impregnation method.The catalytic performance of the catalysts in the vapor-phase oxidation of durene to pyromellitic dianhydride(PMDA)was investigated.The structure of the catalysts was characterized by X-ray diffraction(XRD),Raman spectra(Raman),X-ray photoelectron spectroscopy(XPS),Fourier transform infrared spectroscopy(FT-IR)and H_(2)temperature programmed reduction(H_(2)-TPR).The experimental results showed that the active components of the catalysts were in a highly dispersed state.The doping of cerium increased the oxygen defect and adsorbed oxygen on the catalyst surface,which improved the catalytic performance of the catalyst without changing the existence state of VOon the surface of TiO_(2).When the molar ratio of V to Ce was 1:0.1,the catalytic performance of the Ce-VO/TiO_(2)catalyst was best and the yield of PMDA could reach 82.1%(mass fraction).