Boron nitride supported Pd catalysts for the hydrogenation of lactose
Boron nitride supported Pd catalysts for the hydrogenation of lactose
复制标题
DOI：
10.1016/j.cattod.2013.11.067
复制
发表时间：
2015-03
期刊：
影响因子：
5.3
通讯作者：
Nathalie Meyer;M. Devillers;S. Hermans
中科院分区：
文献类型：
--
作者：
Nathalie Meyer;M. Devillers;S. Hermans
为了寻找合适的乳糖选择加氢合成乳糖醇的催化剂，合成了Pd/h-BN材料。采用湿法和水浸渍法制备了催化剂，并用X射线衍射仪、X射线光电子能谱、透射电子显微镜和CO化学吸附等手段对催化剂进行了表征。在乳糖加氢反应中对它们进行了测试，以评价氮化硼作为载体在该反应中的潜力，并了解催化剂在结构性质方面的需求，并与乳糖的氧化进行直接比较。还制备了Pd/α-Al_2O_3和Pd/γ-Al_2O_3，以评价载体的影响。在所有情况下，WI制备的催化剂都比AI制备的催化剂具有更高的活性和选择性。在这两个反应中，含有许多小于3 nm的Pd颗粒的催化剂都没有活性。乳糖加氢合成乳糖醇最具活性和选择性的催化剂是载体表面的Pd颗粒呈金字塔状，没有小于3 nm的颗粒。这种特殊的形状似乎很适合氢化反应，因为氢的化学吸附可以发生在金字塔的边缘，而乳糖需要平坦的表面，可以吸附在三角金字塔的表面上。
Pd/h-BN materials have been synthesized in order to find an appropriate catalyst for the selective hydrogenation of lactose into lactitol. The catalysts were prepared by wet impregnation (WI) or aqueous impregnation (AI) and characterized by XRD, XPS, TEM and CO chemisorption. They were all tested in the hydrogenation of lactose in order to evaluate the potential of boron nitride as support in this reaction and also to understand the needs in terms of structural properties of the catalyst, in direct comparison with the oxidation of lactose. Pd/α-Al2O3and Pd/γ-Al2O3were also prepared in order to evaluate the influence of the support. In all cases, the catalysts prepared by WI were more active and selective than those prepared by AI. In both reactions, the catalysts containing many Pd particles smaller than 3 nm were not active. The most active and selective catalyst towards lactitol by lactose hydrogenation presented, at the surface of the support, palladium particles of pyramidal shapes and no particles smaller than 3 nm. This particular shape seems to be well suited for the hydrogenation reaction because H2chemisorption can take place on the pyramid edges while lactose, requiring flat surfaces, could adsorb on the triangular pyramid faces.