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Monolayer Support Control and Precise Colloidal Nanocrystals Demonstrate Metal–Support Interactions in Heterogeneous Catalysts
Advanced Materials ( IF 29.4 ) Pub Date : 2021-09-17 , DOI: 10.1002/adma.202104533
Emmett D Goodman 1 , Arun S Asundi 1 , Adam S Hoffman 2 , Karen C Bustillo 3 , Jonathan F Stebbins 4 , Simon R Bare 2 , Stacey F Bent 1 , Matteo Cargnello 1
Affiliation  

Electronic and geometric interactions between active and support phases are critical in determining the activity of heterogeneous catalysts, but metal–support interactions are challenging to study. Here, it is demonstrated how the combination of the monolayer-controlled formation using atomic layer deposition (ALD) and colloidal nanocrystal synthesis methods leads to catalysts with sub-nanometer precision of active and support phases, thus allowing for the study of the metal–support interactions in detail. The use of this approach in developing a fundamental understanding of support effects in Pd-catalyzed methane combustion is demonstrated. Uniform Pd nanocrystals are deposited onto Al2O3/SiO2 spherical supports prepared with control over morphology and Al2O3 layer thicknesses ranging from sub-monolayer to a ≈4 nm thick uniform coating. Dramatic changes in catalytic activity depending on the coverage and structure of Al2O3 situated at the Pd/Al2O3 interface are observed, with even a single monolayer of alumina contributing an order of magnitude increase in reaction rate. By building the Pd/Al2O3 interface up layer-by-layer and using uniform Pd nanocrystals, this work demonstrates the importance of controlled and tunable materials in determining metal–support interactions and catalyst activity.

中文翻译:

单层载体控制和精确的胶体纳米晶体证明多相催化剂中的金属-载体相互作用

活性相和载体相之间的电子和几何相互作用对于确定多相催化剂的活性至关重要,但金属-载体相互作用的研究具有挑战性。在这里,展示了使用原子层沉积 (ALD) 和胶体纳米晶体合成方法的单层控制形成的组合如何产生具有亚纳米级精度的活性和载体相的催化剂,从而允许研究金属-载体交互细节。证明了使用这种方法对 Pd 催化的甲烷燃烧中的载体效应有基本的了解。均匀的 Pd 纳米晶体沉积在 Al 2 O 3 /SiO 2球形载体上,通过控制形态和 Al 制备2 O 3层厚度范围从亚单层到≈4 nm 厚的均匀涂层。观察到催化活性的显着变化取决于位于 Pd/Al 2 O 3界面的 Al 2 O 3的覆盖范围和结构,即使是单个单层氧化铝也有助于反应速率的数量级增加。通过逐层构建 Pd/Al 2 O 3界面并使用均匀的 Pd 纳米晶体,这项工作证明了可控和可调材料在确定金属-载体相互作用和催化剂活性方面的重要性。
更新日期:2021-11-01
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