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金属-有机骨架材料(metal-organic frameworks,MOFs)是一类新型纳米多孔功能材料。由于其独特的结构特征,在催化方面展现出潜在的应用价值。采用分子模拟结合密度泛函理论的计算方法系统地研究了ZIF-8在负载金属Pd、Ag、Pt、Au后的催化活性。结果表明,金属与材料之间主要有3种作用方式,其中以“碳-金属-碳”(C-M-C)形式最为稳定。并且对于同一种方式,ZIF-8负载金属后的稳定性顺序为:Pd>Ag>Pt>Au。同时,利用CO作为探针分子,系统地研究了负载金属后ZIF-8的催化活性,发现这些金属原子的Lewis酸性强弱与其电子接受能力有关,其催化活性顺序为:Pd>Pt>Ag>Au。这为研究利用MOF材料负载金属用于催化提供了参考信息。
Metal-organic frameworks (MOFs) are a new class of nanoporous functional materials. Due to its unique structural features, it shows potential application value in catalysis. The catalytic activity of ZIF-8 on Pd, Ag, Pt, Au was studied systematically by means of molecular simulation combined with density functional theory. The results show that there are three main modes of action between metal and material, of which the most stable is “C-M-C”. And in the same way, the stability order of ZIF-8 metal loading is: Pd> Ag> Pt> Au. At the same time, the catalytic activity of ZIF-8 was investigated systematically using CO as a probe molecule. The Lewis acidity of these metal atoms was found to be related to their electron accepting ability. The order of catalytic activity was Pd> Pt> Ag> Au. This provides a reference for the study of metal loading using MOF for catalysis.