Liu Lichen, Zakharov Dmitri N, Arenal Raul, Concepcion Patricia, Stach Eric A, Corma Avelino
Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas (UPV-CSIC), Av. de los Naranjos s/n, 46022, Valencia, Spain.
Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York, 11973, USA.
Nat Commun. 2018 Feb 8;9(1):574. doi: 10.1038/s41467-018-03012-6.
Understanding the behavior and dynamic structural transformation of subnanometric metal species under reaction conditions will be helpful for understanding catalytic phenomena and for developing more efficient and stable catalysts based on single atoms and clusters. In this work, the evolution and stabilization of subnanometric Pt species confined in MCM-22 zeolite has been studied by in situ transmission electron microscopy (TEM). By correlating the results from in situ TEM studies and the results obtained in a continuous fix-bed reactor, it has been possible to delimitate the factors that control the dynamic agglomeration and redispersion behavior of metal species under reaction conditions. The dynamic reversible transformation between atomically dispersed Pt species and clusters/nanoparticles during CO oxidation at different temperatures has been elucidated. It has also been confirmed that subnanometric Pt clusters can be stabilized in MCM-22 crystallites during NO reduction with CO and H.
了解亚纳米级金属物种在反应条件下的行为和动态结构转变，将有助于理解催化现象，并开发基于单原子和团簇的更高效、稳定的催化剂。在这项工作中，通过原位透射电子显微镜（TEM）研究了限制在MCM-22沸石中的亚纳米级Pt物种的演化和稳定性。通过将原位TEM研究结果与连续固定床反应器中获得的结果相关联，有可能确定在反应条件下控制金属物种动态团聚和再分散行为的因素。阐明了在不同温度下CO氧化过程中原子分散的Pt物种与团簇/纳米颗粒之间的动态可逆转变。还证实了在CO和H还原NO的过程中，亚纳米级Pt团簇可以在MCM-22微晶中稳定存在。
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