The Smart Materials Research Center, Southern Federal University, Sladkova 178/24, Rostov-on-Don, 344090, Russia.
Faraday Discuss. 2018 Sep 3;208(0):287-306. doi: 10.1039/c7fd00224f.
Functionalization of metal-organic frameworks with metal nanoparticles (NPs) is a promising way for producing advanced materials for catalytic applications. We present the synthesis and in situ characterization of palladium NPs encapsulated inside a functionalized UiO-67 metal-organic framework. The initial structure was synthesized with 10% of PdCl2bpydc moieties with grafted Pd ions replacing standard 4,4'-biphenyldicarboxylate linkers. This material exhibits the same high crystallinity and thermal stability of standard UiO-67. Formation of palladium NPs was initiated by sample activation in hydrogen and monitored by in situ X-ray powder diffraction and X-ray absorption spectroscopy (XAS). The reduction of PdII ions to Pd0 occurs above 200 °C in 6% H2/He flow. The formed palladium NPs have an average size of 2.1 nm as limited by the cavities of UiO-67 structure. The resulting material showed high activity towards ethylene hydrogenation. Under reaction conditions, palladium was found to form a carbide structure indicated by operando XAS, while formation of ethane was monitored by mass spectroscopy and infra-red spectroscopy.
功能化金属-有机骨架与金属纳米粒子（NPs）的结合是制备用于催化应用的先进材料的一种很有前途的方法。我们介绍了钯纳米粒子封装在功能化 UiO-67 金属-有机骨架中的合成和原位表征。该初始结构是用 10%的 PdCl2bpydc 部分合成的，其中接枝的钯离子取代了标准的 4,4'-联苯二甲酸酯连接体。这种材料表现出与标准 UiO-67 相同的高结晶度和热稳定性。钯纳米粒子的形成是通过在氢气中对样品进行活化并通过原位 X 射线粉末衍射和 X 射线吸收光谱（XAS）进行监测而引发的。在 6% H2/He 流量下，PdII 离子还原为 Pd0 的温度高于 200°C。形成的钯纳米粒子的平均尺寸为 2.1nm，这是由 UiO-67 结构的空腔限制的。所得材料对乙烯加氢具有高活性。在反应条件下，通过 operando XAS 发现钯形成了碳化物结构，同时通过质谱和红外光谱监测到乙烷的形成。
