不同晶型TiO_2负载镍催化剂催化顺酐液相加氢

Liquid Phase Hydrogenation of Maleic Anhydride over Ni/TiO_2 Catalysts with Different TiO_2 Polymorphs

分别以锐钛矿相Ti O2和金红石相Ti O2为载体,采用等体积浸渍法制备了Ni/Ti O2催化剂,考察了其催化顺酐液相加氢性能.采用氮气吸附-脱附、氢气程序升温还原(H2-TPR)、X射线衍射(XRD)、氢气程序升温脱附(H2-TPD)及X射线光电子能谱(XPS)等技术对催化剂进行了表征.催化剂评价结果表明,以锐钛矿型Ti O2为载体催化剂的C O加氢活性明显高于以金红石型Ti O2为载体的催化剂.这主要是由于在还原过程中锐钛矿型Ti O2较易被还原,产生了较高浓度的氧缺陷位,该氧缺陷位可通过接受C O中O的孤对电子来活化C O,促使其与H2发生加氢反应,进而使催化剂表现出较高的C O加氢活性.

Ni / Ti O2 catalysts with anatase and rutile titania as supports were prepared via the incipient impregnation method and were applied in the liquid phase hydrogenation of maleic anhydride. All catalysts were characterized by N2 physical adsorption-desorption,H2-temperature programmed reduction（ H2-TPR）,X-ray diffraction（ XRD）,H2-temperature programmed desorption（ H2-TPD） and X-ray photoelectron spectroscopy（ XPS）. The evaluation results show that the activity of C O hydrogenation of catalyst with anatase Ti O2 as support was significantly higher than that with rutile Ti O2 as support. The higher activity of C O hydrogenation was attributed to a higher concentration of the oxygen vacancies produced during the reduction process.Oxygen vacancies could promote the hydrogenation of C O group by accepting lone pair of electrons of oxygen in C O group.