Generation of subnanometric platinum with high stability during transformation of a 2D zeolite into 3D

[EN] Single metal atoms and metal clusters have attracted much attention thanks to their advantageous capabilities as heterogeneous catalysts. However, the generation of stable single atoms and clusters on a solid support is still challenging. Herein, we report a new strategy for the generation of single Pt atoms and Pt clusters with exceptionally high thermal stability, formed within purely siliceous MCM-22 during the growth of a two-dimensional zeolite into three dimensions. These subnanometric Pt species are stabilized by MCM-22, even after treatment in air up to 540 degrees C. Furthermore, these stable Pt species confined within internal framework cavities show size-selective catalysis for the hydrogenation of alkenes. High-temperature oxidation-reduction treatments result in the growth of encapsulated Pt species to small nanoparticles in the approximate size range of 1 to 2 nm. The stability and catalytic activity of encapsulated Pt species is also reflected in the dehydrogenation of propane to propylene.This work was funded by the Spanish Government (Consolider Ingenio 2010-MULTICAT (CSD2009-00050) and MAT2014-52085-C2-1-P) and by the Generalitat Valenciana (Prometeo). The Severo Ochoa Program (SEV-2012-0267) is gratefully acknowledged. L.L. thanks ITQ for a contract. The authors also thank the Microscopy Service of UPV for the TEM and STEM measurements. The HAADF-HRSTEM works were conducted in the Laboratorio de Microscopias Avanzadas (LMA) at the Instituto de Nanociencia de Aragon (INA)-Universidad de Zaragoza (Spain), a Spanish ICTS National Facility. Some of the research leading to these results has received funding from the European Union Seventh Framework Program under Grant Agreement 312483-ESTEEM2 (Integrated Infrastructure Initiative-I3). R.A. also acknowledges funding from the Spanish Ministerio de Economia y Competitividad (FIS2013-46159-C3-3-P) and the European Union Horizon 2020 research and innovation programme under the Marie Sldodowska-Curie grant agreement No. 642742.Liu, L.; Díaz Morales, UM.; Arenal, R.; Agostini, G.; Concepción Heydorn, P.; Corma Canós, A. (2017). Generation of subnanometric platinum with high stability during transformation of a 2D zeolite into 3D. Nature Materials. 16(1):132-138. https://doi.org/10.1038/NMAT4757132138161Boronat, M., Leyva-Perez, A. & Corma, A. Theoretical and experimental insights into the origin of the catalytic activity of subnanometric gold clusters: attempts to predict reactivity with clusters and nanoparticles of gold. Acc. Chem. Res. 47, 834–844 (2014).Flytzani-Stephanopoulos, M. & Gates, B. C. Atomically dispersed supported metal catalysts. Ann. Rev. Chem. Bio. Eng. 3, 545–574 (2012).Gates, B. C. Supported metal clusters: synthesis, structure, and catalysis. Chem. 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