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Reaction pathway for coke-free methane steam reforming on a Ni/CeO2 catalyst: Active sites and role of metal-support interactions

Agustín Salcedo1,2*, Pablo G. Lustemberg3,4*, Ning Rui5, Robert M. Palomino5, Zongyuan Liu5, Slavomir Nemsak6, Sanjaya D. Senanayake5, José A. Rodriguez5, M. Verónica Ganduglia-Pirovano3*, Beatriz Irigoyen1,2*

1 Universidad de Buenos Aires (UBA), Facultad de Ingeniería, Departamento de Ingeniería Química, Ciudad Universitaria, C1428EGA Buenos Aires, Argentina

2 Instituto de Tecnologías de Hidrógeno y Energías Sostenibles (ITHES, CONICET-UBA), Ciudad Universitaria, C1428EGA Buenos Aires, Argentina

3 Instituto de Catálisis y Petroleoquímica (ICP, CSIC), 28049 Madrid, Spain

4 Instituto de Física Rosario (IFIR, CONICET-UNR), S2000EKF Rosario, Santa Fe, Argentina

5 Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, USA

6 Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA

* Corresponding authors emails: asalcedo@fi.uba.ar, p.lustemberg@csic.es, vgp@icp.csic.es, beatriz@di.fcen.uba.ar
DOI10.24435/materialscloud:ct-c6 [version v1]

Publication date: Jun 01, 2021

How to cite this record

Agustín Salcedo, Pablo G. Lustemberg, Ning Rui, Robert M. Palomino, Zongyuan Liu, Slavomir Nemsak, Sanjaya D. Senanayake, José A. Rodriguez, M. Verónica Ganduglia-Pirovano, Beatriz Irigoyen, Reaction pathway for coke-free methane steam reforming on a Ni/CeO2 catalyst: Active sites and role of metal-support interactions, Materials Cloud Archive 2021.83 (2021), doi: 10.24435/materialscloud:ct-c6.

Description

Methane steam reforming (MSR) plays a key role in the production of syngas and hydrogen from natural gas. The increasing interest in the use of hydrogen for fuel cell applications demands the development of catalysts with high activity at reduced operating temperatures. Ni-based catalysts are promising systems because of their high activity and low cost, but coke formation generally poses a severe problem. Studies of ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) indicate that CH4/H2O gas mixtures react with Ni/CeO2(111) surfaces to form OH, CHx and CHxO at 300 K. All these species are easy to form and desorb at temperatures below 700 K when the rate of the MSR process accelerates. Density functional theory (DFT) modeling of the reaction over ceria-supported small Ni nanoparticles predicts relatively low activation barriers between 0.3–0.7 eV for the complete dehydrogenation of methane to carbon and the barrierless activation of water at interfacial Ni sites. Hydroxyls resulting from water activation allow CO formation via a COH intermediate with a barrier of about 0.9 eV, which is much lower than that through a pathway involving lattice oxygen from ceria. Neither methane nor water activation are rate-determining steps, and the OH-assisted CO formation through the COH intermediate constitutes a low-barrier pathway that prevents carbon accumulation. The interaction between Ni and the ceria support and the low metal loading are crucial for the reaction to proceed in a coke-free and efficient way. These results could pave the way for further advances in the design of stable and highly active Ni-based catalysts for hydrogen production.

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File name Size Description
README.txt
MD5md5:3809f6373e9e912c213bd7a4717e8bb0
737 Bytes Readme file
MSR_DFT_data.zip
MD5md5:0844eb391fc4262e14555391acf1674d
205.7 MiB DFT calculations described in Figures S1 and S7–S12 of the Supporting Information of the associated paper.

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Keywords

Methane Steam reforming Hydrogen Nickel Ceria DFT

Version history:

2021.83 (version v1) [This version] Jun 01, 2021 DOI10.24435/materialscloud:ct-c6