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采用共沉淀法制备了铜锌铝类水滑石前驱体,经焙烧和还原后制得铜基催化剂。采用XRD、H2-TPR、H2-TPD、NH3-TPD和CO2-TPD等表征手段并结合甘油氢解反应评价,研究了类水滑石前驱体的老化对催化剂结构和性能的影响,考察了反应条件对催化剂甘油氢解反应性能的影响。结果表明,老化有利于形成结构更为完整的类水滑石前驱体,但对铜物种的还原性能未造成显著影响。与由未老化前驱体制备的催化剂相比,由老化前驱体制备的铜锌铝催化剂具有较大Cu表面及较大酸量,但表面碱中心数量较低,从而该催化剂具有较好的甘油氢解活性及稳定性。在220℃、H2压力3.0 MPa、n(H2)/n(甘油)为18.9、甘油重时空速1.26 h-1及质量分数为60%甘油水溶液的条件下,经老化前驱体制备的铜锌铝催化剂上甘油转化率接近100%、1,2-丙二醇选择性约为96%。
Copper-zinc-aluminum hydrotalcite precursors were prepared by coprecipitation method. After calcination and reduction, copper-based catalysts were prepared. The effects of aging of hydrotalcite-like precursors on the structure and properties of catalysts were investigated by XRD, H2-TPR, H2-TPD, NH3-TPD and CO2-TPD methods. On the catalytic performance of hydrogenolysis of glycerol. The results show that aging is conducive to the formation of a more intact hydrotalcite-like precursor, but has no significant effect on the reduction performance of copper species. Compared with the catalyst prepared from unaged precursor, the Cu-Zn-Al catalyst prepared from the aged precursor has larger Cu surface and larger amount of acid, but the number of surface alkali centers is lower, so the catalyst has better glycerol Deactivation and stability. Under the conditions of 220 ℃, H2 pressure 3.0 MPa, n (H2) / n (glycerol) 18.9, glycerol WHSV 1.26 h-1 and 60% glycerol aqueous solution, The conversion of glycerol on the catalyst is close to 100% with 1,2-propanediol selectivity of about 96%.