Tracking Rh Atoms in Zeolite HY: First Steps of Metal Cluster Formation and Influence of Metal Nuclearity on Catalysis of Ethylene Hydrogenation and Ethylene Dimerization

Journal Article · Thu Jul 07 04:00:00 EDT 2016 · Journal of Physical Chemistry Letters

DOI:https://doi.org/10.1021/acs.jpclett.6b01153· OSTI ID:1298393

Yang, Dong; Xu, Pinghong; Browning, Nigel D.; Gates, Bruce C.

The initial steps of rhodium cluster formation from zeolite-supported mononuclear Rh(C2H4)2 complexes in H2 at 373 K and 1 bar were investigated by infrared and extended X-ray absorption fine structure spectroscopies and scanning transmission electron microscopy (STEM). The data show that ethylene ligands on the rhodium react with H2 to give supported rhodium hydrides and trigger the formation of rhodium clusters. STEM provided the first images of the smallest rhodium clusters (Rh2) and their further conversion into larger clusters. The samples were investigated in a plug-flow reactor as catalysts for the conversion of ethylene + H2 in a molar ratio of 4:1 at 1 bar and 298 K, with the results showing how the changes in catalyst structure affect the activity and selectivity; the rhodium clusters are more active for hydrogenation of ethylene than the single-site complexes, which are more selective for dimerization of ethylene to give butenes

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1298393
• Report Number(s): PNNL-SA-118513; 48583
• Journal Information: Journal of Physical Chemistry Letters, Journal Name: Journal of Physical Chemistry Letters Journal Issue: 13 Vol. 7; ISSN 1948-7185
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

Environmental Molecular Sciences Laboratory
STEM image
Zeolite HY
rhodium
rhodium cluster formation
single-site catalyst
surface pair sites