Structural modulation and direct measurement of subnanometric bimetallic PtSn clusters confined in zeolites

Abstract

Modulating the structures of subnanometric metal clusters at the atomic level is a great synthetic and characterization challenge in catalysis. Here we show how the catalytic properties of subnanometric Pt clusters (0.5-0.6 nm) confined in the sinusoidal 10R channels of purely siliceous MFI zeolite modulate upon introduction of partially reduced Sn species that interact with the noble metal at the metal/support interface. The low mobility of Sn in H2 over an extended period of time (>6 h) even at high temperatures (e.g. 600 ⁰C), which is determined by only a few additional Sn atoms added to the Pt clusters. Such structural features, which are not immediately visible by conventional characterization techniques and can be laid out after combination of in situ EXAFS, HAADF-STEM and CO-IR data, is key to provide one-order of magnitude lower deactivation rate in the propane dehydrogenation reaction while maintaining high intrinsic (initial) catalytic activity. Pt foil a12 2.763 ± 0

Effects of Crystallite Sizes of Pt/HZSM-5 Zeolite Catalysts on the Hydrodeoxygenation of Guaiacol

“…Unfortunately, bifunctional zeolite-supported noble metals also have several disadvantages. The metal aggregation on the carrier surface during the high-temperature oxidation–reduction and limited mass transport of guest molecules inside the micropores significantly decrease their catalytic activity and cause fast catalyst deactivation, especially in the case of bulky oxygenated compounds [ 19 , 20 ].…”

Multiatom Catalysts for Energy‐Related Electrocatalysis

“…Spatially confining metal atoms inside the molecular‐scale cavities can effectively prevent their migration and has been considered one of the most straightforward synthetic methods for MACs. The spatial confinement can be realized with the aid of porous materials (i.e., zeolites, [ 21,22 ] metal–organic frameworks (MOFs), [ 23 ] covalent‐organic frameworks (COFs), [ 24 ] and nanostructured carbon [ 25 ] ) or within specific crystal structures. [ 26,27 ] Such delicate nanoscale structures can effectively confine the clusters, ensuring the formation of monodispersed MACs with high uniformity.…”

Design and tailoring of advanced catalytic process for light alkanes upgrading

“…Corma and coworkers studied the confinement of Sndecorated Pt clusters within the channels of purely siliceous MFI zeolite for the ODHP. 141 It was suggested that the formation of subnanometric PtSn clusters (0.5-0.6 nm) in terms of their interaction by selective location in the sinusoidal 10R channels of MFI zeolite as shown in Figure 7A was the key to achieve propane conversion of $20% and propylene selectivity of >97%, which had negligible decreases after 70 hours stability test. Hermans and coworkers found that hexagonal boron nitride and boron nitride nanotubes also exhibited high catalytic performances of 14% propane conversion, 79% propene and 12% ethylene selectivity, in which the O-terminated armchair boron nitride edges were suggested as the main catalytic active sites.…”

“…Reproduced with permission: Copyright 2020, Springer Nature. 141 B, Structural representation of the metal-organic framework (MOF) support, NU-1000, as well as the two preparation methods of Co-based catalysts for propane oxidative dehydrogenation of ethane (ODH) catalysis. Reproduced with permission: Copyright 2017, American Chemical Society 145 of promoter ions including Ni(II), Zn(II), Al(III), Ti(IV) and Mo(VI), were selected to decorate the NU-1000 followed by Co(II) ion deposition to prepare the bimetallic-oxo, hydroxo, aqua clusters.…”