竞争吸附剂对Pt-SDB催化剂活性组分分布的影响

Effects of Competitive Adsorbents on Distribution of Active Components in Pt-SDB Catalysts

摘要: 为了探究竞争吸附剂对Pt-SDB催化剂活性组分Pt分布及催化活性的影响，采用柠檬酸、酒石酸、草酸对4 mm粒径柱形聚苯乙烯–二乙烯基苯(SDB)进行浸渍，然后负载铂制备Pt-SDB疏水催化剂。凭借亚甲基黄作为显色剂分析竞争吸附剂对活性组分分布的影响，并通过水氢液相催化交换反应对催化剂活性进行测试。实验结果表明：柠檬酸、酒石酸和草酸预浸渍SDB载体时的吸附机理相同，都是先占据SDB载体的表层，之后随着竞争吸附剂浓度的增大，酸在载体内的钻进深度逐渐增大；相同的酸浓度和预浸渍时间下，柠檬酸于SDB载体内的钻进深度最大，酒石酸钻进深度最小，草酸居中；不同浓度竞争吸附剂同样预浸渍30 min的情况下，对柱形Pt-SDB疏水催化剂而言，柠檬酸、酒石酸和草酸的较佳预浸渍浓度为0.3 mol/L，分别对催化剂活性有不同程度的提升作用。

Abstract: In order to explore the effect of competing adsorbents on the Pt distribution and catalytic activity of the active component Pt-SDB catalyst, citric acid, tartaric acid, and oxalic acid were used to impreg-nate 4 mm particle size cylindrical polystyrene-divinylbenzene (SDB), and then loaded with citric acid, tartaric acid, and oxalic acid. Pt-SDB hydrophobic catalyst prepared from platinum. The influ-ence of competing adsorbents on the distribution of active components was analyzed by using methylene yellow as a color developer, and the catalyst activity was tested by the liquid-phase cat-alytic exchange reaction of water and hydrogen. The experimental results show that the adsorption mechanism of citric acid, tartaric acid and oxalic acid pre-impregnated with SDB carrier is the same, which occupies the surface layer of SDB support first, and then gradually increases the drilling depth of acid in the carrier with the increase of the concentration of competitive adsorbents; under the same acid concentration and pre-impregnation time, citric acid has the largest drilling depth in the SDB carrier, the drilling depth of tartaric acid is the smallest, and the oxalic acid is centered; under the same pre-impregnation of different concentrations of competitive adsorbents for 30 min, for the cylindrical Pt-SDB hydrophobic catalyst. The preferred pre-maceration concentrations of cit-ric acid, tartaric acid and oxalic acid were 0.3 mol/L, which had different degrees of enhancement effect on catalyst activity.