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以Cu-Zn-Al和Cu-Mg-Al类水滑石为前体经焙烧、还原制备了铜基催化剂,采用XRD、H2-TPR、N2吸附、H2-TPD、NH3-TPD、CO2-TPD及活性评价等方法,研究了M2+离子(M2+=Zn2+或Mg2+)及n(M2+)/n(Al3+)比对催化剂结构和甘油氢解反应性能的影响。结果表明,经450℃焙烧后,类水滑石转变为由尖晶石和/或氧化物组成的氧化态前驱体,再经270℃还原后制得高分散Cu催化剂。随氧化铝含量提高,催化剂比表面及酸量增加。Cu-Zn-Al催化剂表面氢吸附量大于CuMg-Al。Cu-Mg-Al催化剂碱性强于Cu-Zn-Al。Cu-Zn-Al[n(Cu)∶n(Zn)∶n(Al)=1∶1∶4]催化剂具有较佳甘油氢解活性及1,2-丙二醇选择性,这与其具有较多表面铜中心、较大酸量及Zn物种参与氢吸附有关。此外,Cu-Mg-Al催化剂表面铜中心和碱中心可能存在协同作用促进甘油氢解反应。
The Cu-Zn-Al and Cu-Mg-Al hydrotalcite precursors were calcined and reduced to prepare copper-based catalysts. XRD, H2-TPR, N2 adsorption, H2-TPD, NH3-TPD, The effects of M2 + ions (M2 + = Zn2 + or Mg2 +) and n (M2 +) / n (Al3 +) ratio on the structure of the catalyst and the hydrogenolysis reaction of glycerol were studied. The results show that after hydrothermal calcination at 450 ℃, the hydrotalcite - like hydrotalcite transforms into the precursor of oxide in the form of spinel and / or oxide. After reduction at 270 ℃, a highly dispersed Cu catalyst is obtained. With the increase of alumina content, the specific surface area of catalyst and acid amount increased. The amount of hydrogen adsorption on Cu-Zn-Al catalyst surface is larger than that of CuMg-Al. Cu-Mg-Al catalyst is more alkaline than Cu-Zn-Al. Cu-Zn-Al [n (Cu): n (Zn): n (Al) = 1: 1: 4] has better glycerol hydrogenolysis and 1,2-propanediol selectivity, Copper center, larger acid amount and Zn species are involved in hydrogen adsorption. In addition, Cu-Mg-Al catalyst surface copper center and base may exist synergies to promote glycerol hydrogenolysis.