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Composition-Tuned Pt-Skinned PtNi Bimetallic Clusters as Highly Efficient Methanol Dehydrogenation Catalysts

Ting-Wei Liao, Anupam Yadav, Piero Ferrari, Yubiao Niu, Xian-Kui Wei, Jerome Vernieres, Kuo-Juei Hu, Marc Heggen, Rafal E. Dunin-Borkowski, Richard Palmer Orcid Logo, Kari Laasonen, Didier Grandjean, Ewald Janssens, Peter Lievens

Chemistry of Materials, Volume: 31, Issue: 24, Pages: 10040 - 10048

Swansea University Author: Richard Palmer Orcid Logo

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DOI (Published version): 10.1021/acs.chemmater.9b02824

Abstract

Platinum is the most active anode and cathode catalyst in next-generation fuel cells using methanol as liquid source of hydrogen. Its catalytic activity can be significantly improved by alloying with 3d metals, although a precise tuning of its surface architecture is still required. Herein, we repor...

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Published in: Chemistry of Materials
ISSN: 0897-4756 1520-5002
Published: American Chemical Society (ACS) 2019
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URI: https://cronfa.swan.ac.uk/Record/cronfa53118
Abstract: Platinum is the most active anode and cathode catalyst in next-generation fuel cells using methanol as liquid source of hydrogen. Its catalytic activity can be significantly improved by alloying with 3d metals, although a precise tuning of its surface architecture is still required. Herein, we report the design of a highly active low-temperature (below 0 °C) methanol dehydrogenation anode catalyst with reduced CO poisoning based on ultralow amount of precisely defined PtxNi1–x (x = 0 to 1) bimetallic clusters (BCs) deposited on inert flat oxides by cluster beam deposition. These BCs feature clear composition-dependent atomic arrangements and electronic structures stemming from their nucleation mechanism, which are responsible for a volcano-type activity trend peaking at the Pt0.7Ni0.3 composition. Our calculations reveal that at this composition, a cluster skin of Pt atoms with d-band centers downshifted by subsurface Ni atoms weakens the CO interaction that in turn triggers a significant increase in the methanol dehydrogenation activity.
Item Description: STEM images and histograms of diameter distributions of clusters; DFT calculations of the mixing energy of tetramers; atomic-scale HAADF–STEM image of Au0.7Ag0.3 BC; TPD traces for methanol-d4 desorption from a SiO2 surface; CD3 mass signal (after background subtraction) measured during methanol decomposition; CO2 signal collected during methanol decomposition; overview of the CO binding energy as a function of d-band population for various Pt surfaces in Pt353Ni106and Pt4174Ni144 clusters; CO–Pt binding energy (in eV) for various Pt adsorption sites in Pt353Ni106 and Pt417Ni144; d-electron population of the atoms in Pt353Ni106 and Pt417Ni144 calculated using the Löwdin and Mulliken charge analysis methods; average charges on the Pt and Ni atoms in the Pt353Ni106 and Pt417Ni144 BCs, analyzed using four different charge decomposition methods; and additional material including a comparison of the preparation and structures of Au–Ag BCs with Pt–Ni BCs, TPD experiment and analysis procedures, and details on the DFT calculations (PDF)pdfcm9b02824_si_001.pdf (730.78 kb)
College: Faculty of Science and Engineering
Issue: 24
Start Page: 10040
End Page: 10048

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