Role of the Secondary Metal in Ordered and Disordered Pt−M Intermetallic Nanoparticles: An Example of Pt3Sn Nanocubes for the Electrocatalytic Methanol Oxidation
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Date
2021
Journal Title
Journal ISSN
Volume Title
Publisher
ACS Catalysis
Abstract
When comparing alloy catalysts with different degrees of ordering, it is
important to maintain surface facets to understand the effect of different arrangements of
surface atoms. This is even more important when both metals are involved in the reaction
steps, which is the case of Pt3Sn for the methanol oxidation reaction (MOR). We have
prepared 95 and 60% ordered Pt3Sn nanocubes with {100} facets for the MOR. We show
that the Sn atoms in the 60% ordered Pt3Sn nanocubes can be electrochemically oxidized
to Sn4+, whereas the Sn atoms in the 95% ordered Pt3Sn nanocubes are more resistant to
oxidation. The Sn4+ in the disordered catalysts makes them more active than the ordered
catalysts. At low overpotentials, the electrochemically formed Sn4+ in the 60% ordered
Pt3Sn nanocubes bind OH, oxidizing the CO intermediate adsorbed on Pt more efficiently.
At high overpotentials, Sn4+ prevents the passivation of the Pt sites due to adsorption of
OH. These effects lead to a 5.6 times higher activity of the 60% ordered nanocubes
compared to the 95% ordered nanocubes. These results illustrate the importance in
catalyst design of controlling the environment and especially the atoms neighboring Pt for intermetallic Pt−M electrocatalysts.
Description
Keywords
Intermetallic, Pt alloys, Oxidation reaction, Methanol oxidation reaction, Pt3Sn
Citation
Chen, H. S., Benedetti, T. M., Lian, J., Cheong, S., O’Mara, P. B., Sulaiman, K. O., ... & Tilley, R. D. (2021). Role of the Secondary Metal in Ordered and Disordered Pt–M Intermetallic Nanoparticles: An Example of Pt3Sn Nanocubes for the Electrocatalytic Methanol Oxidation. ACS Catalysis, 11(4), 2235-2243. https://dx.doi.org/10.1021/acscatal.0c05370