ZnO-ZrO_(2)催化剂上CO_(2)辅助乙烷氧化脱氢制乙烯的研究

CO_(2)-assisted oxidative dehydrogenation of ethane to ethylene over the ZnO-ZrO_(2) catalyst

以焙烧商用氢氧化锆(Zr(OH)_(4))得到的ZrO_(2)为载体,通过沉积-沉淀法制备了ZnO-ZrO_(2)催化剂,并在873 K下对该催化剂上CO_(2)辅助的乙烷氧化脱氢反应(CO_(2)-ODHE)的催化性能进行了评价。利用X射线衍射(XRD)、扫描电镜(SEM)、拉曼光谱(Raman)、高分辨透射电镜(HRTEM)、X射线光电子能谱(XPS)、CO_(2)程序升温脱附(CO_(2)-TPD)等技术对ZnO-ZrO_(2)催化剂的表面物理化学性质和形貌进行了表征。结果表明,在5%ZnO-ZrO_(2)催化剂上,ZnO掺入到了ZrO_(2)的表面晶格之中,在催化剂表面产生了高度分散的ZnO物种和氧缺陷区域。5%ZnO-ZrO_(2)催化剂可以选择性地剪裁乙烷C-H键,抑制C-C键的断裂,具备良好的催化性能。210μmol/(g_(cat)·min)的C2H4形成率可以与贵金属和过渡金属碳化物催化剂的报道数据接近。此外,还对ZnO-ZrO_(2)催化剂上CO_(2)-ODHE反应可能的反应机制进行了讨论。

The ZnO-ZrO_(2) catalyst was prepared by the deposition-precipitation method using ZrO_(2) as the carrier obtained from calcining commercial zirconium hydroxide(Zr(OH)_(4)).And the catalytic performance was evaluated at 873 K in CO_(2)-assisted ethane oxidative dehydrogenation reaction(CO_(2)-ODHE).The physical-chemical properties and morphology were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM),Raman spectra,High-resolution transmission electron microscopy(HRTEM),X-ray photoelectron spectra(XPS),CO_(2) temperature-programmed desorption(CO_(2)-TPD).The results show that ZnO were doped into the surface lattice of ZrO_(2) on the 5%ZnO-ZrO_(2) catalyst,generating highly dispersed ZnO species and oxygen-deficient regions on catalyst surface.5%ZnO-ZrO_(2) catalyst could selectively breaking C−H bond instead of C−C bond,delivering excellent catalytic performance.210μmol/(g_(cat)·min)of C2H4 formation rate could compare favorably with the data reported on noble metal and transition metal carbides.Additionally,the possible mechanism is discussed.