一锅溶剂蒸发诱导自组装法制备助剂体相分布的Pd-Ba-Zn/γ-Al_2O_3催化剂及其蒽醌加氢性能

One-pot solvent evaporation induced self-assembly synthesis of Pd-Ba-Zn/γ-Al_2O_3 catalyst with homogeneous distribution of the promoters and its hydrogenation performance of anthraquinone

分别采用一锅溶剂蒸发诱导自组装法和等体积浸渍法制备了Ba-、Zn-助剂体相分布和表相分布的0.4%Pd-2.5%Ba-3.0%Zn/γ-Al_2O_3催化剂,并将其用于催化蒽醌加氢制氢蒽醌反应。采用XRD、TEM、SEM、EDS、N_2吸附-脱附、XPS和高效液相色谱等表征与测试手段,对比研究了上述助剂引入及其分布方式对催化剂微结构和催化性能的影响。结果表明:添加Ba-、Zn-助剂后催化剂的最高氢化效率和氢化稳定性均有提高;Ba-、Zn-助剂由常规的表相分布变为体相分布后,催化剂的稳定性进一步提高,而氢化效率和蒽醌循环回收率基本相当。和常规助剂表相分布催化剂的制备过程相比,制备助剂体相分布的催化剂时,Ba-、Zn-在制备载体前体时一步引入,省去了分步浸渍助剂前体盐和后续的干燥、焙烧等过程,因而制备工艺大大简化、能耗大幅度降低、制备效率显著提高。

Two 0.4%Pd-2.5%Ba-3.0%Zn/γ-Al_2O_3 catalysts with homogeneous distribution and surface distribution of Ba-and Zn-promoters were prepared via one-pot solvent evaporation induced self-assembly method and incipient-wetness impregnation method,respectively.The catalysts were evaluated in anthraquinone hydrogenation reaction for preparing hydroanthraquinone.Effects of the introduction of the two promoters and their distribution methods on the microstructures and catalytic performance of the catalysts were comparatively studied by XRD,TEM,SEM,EDS,N_2adsorption-desorption,XPS and high performance liquid chromatography.The results showed that,both of the maximum hydrogenation efficiency and stability of the catalysts increase after introducing the promoters.When distribution of the promoters was changed from surface distribution to homogeneous distribution,the stability of the catalyst is further improved,but its hydrogenation efficiency and recycling rate of anthraquinone is almost the same. In comparison with the conventional preparation process of the catalyst with surface distribution of the promoters,Ba-and Zn-were simultaneously introduced when preparing its precursor of γ-Al2 O3 with homogeneous distribution of the promoters. The new method has significant advantages of avoiding the impregnation towards the precursors of the promoters and the subsquent drying,calcination processes,and thus greatly simplifies the preparation process,dramatically reduces the energy consumption,and significantly improves the preparation efficiency.