关键词: 类水滑石催化剂, VO_X/Mg-Al-O, 负载量, 氧化脱氢, 氧物种

Abstract: Hydrotalcite-type materials of VO_X/Mg-Al-O with different V∶（Mg+Al）ratios have been prepared with isometric impregnation method，and characterized by X-ray diffraction，N₂-adsorption-desorption，FT-IR and H₂-TPR techniques. The relationship between catalysts′surface properties and the oxidative dehydrogenation performance of cyclohexane to cyclohexene was investigated in detail. The experimental results showed that the isolated and polymeric VO₄ species on the catalyst surface were present at low vanadium loading of lower than 4 wt%，which could be reduced more easily than samples with higher vanadium loading. With the increasing of vanadiumloading，mixed magnesium vanadate compounds appeared on the catalyst surface，which were difficult to be reduced by hydrogen. Under the experimental conditions of 475 ℃ ，hydrocarbon oxygen ration of 2 ，airflow 100 mL/min and the vanadium loading of 4 wt%，a better catalytic performance of cyclohexane oxidative dehydrogenation to cyclohexene could be obtained. It can be suggested that low VO_X species on the surface are the active sites for the reaction.

Key words: hydrotalcite -like compound catalysts, VO_X/Mg-Al-O catalyst, loading, oxidative dehydrogenation, oxygen species