Explicit detection of the mechanism of platinum nanoparticle shape control by polyvinylpyrrolidone

Ye, Jin-Yu, Attard, Gary Anthony, Brew, Ashley, Zhou, Zhi-Yu, Sun, Shi-Gang, Morgan, David John ORCID: https://orcid.org/0000-0002-6571-5731 and Willock, David James ORCID: https://orcid.org/0000-0002-8893-1090 2016. Explicit detection of the mechanism of platinum nanoparticle shape control by polyvinylpyrrolidone. Journal of Physical Chemistry C 120 (14) , pp. 7532-7542. 10.1021/acs.jpcc.5b10910

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Abstract

The irreversible adsorption of polyvinylpyrrolidone (PVP) on a series of well-defined platinum single crystal electrode surfaces has been investigated using voltammetry, ex situ XPS and DFT calculations. It is found that the adsorption of PVP is highly structure sensitive with strong adsorption exhibited by step and {100} terrace sites with only weak inter-actions observed between PVP and Pt{111} terraces, at least at low PVP surface concentrations. Subsequent investiga-tions using CO electrooxidation confirmed that blocking of platinum surface sites by PVP towards CO chemisorption was marked for Pt{100} terraces but hardly occurred at all at Pt{111} terraces. Density Functional Theory calculations also confirmed that the monomer of PVP interacts more strongly with Pt{100} compared to Pt{111} sites (-142 and -125 kJ mol-1 respectively). Ex situ XPS studies suggested that the main PVP-Pt interaction is associated with charge trans-fer from the carbonyl substituent of PVP towards the metal surface in accordance with earlier studies of PVP adsorbed on polycrystalline platinum surfaces. Irreversible adsorption of Pt adatoms onto Pt{hkl} surfaces with and without PVP - surface modification demonstrated a marked preference for {100} facet formation on Pt{100} surfaces but no corre-sponding preferential {111} facet growth on Pt{111} when PVP was present. Hence, the shape control exhibited by PVP in expediting the formation of cubic Pt nanoparticles is explicitly confirmed as arising from relatively weak PVP chemisorption on Pt{111} facets at low PVP surface loading.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Advanced Research Computing @ Cardiff (ARCCA) Cardiff Catalysis Institute (CCI) Chemistry
Subjects:	Q Science > QD Chemistry
Uncontrolled Keywords:	Platinum Nanoparticles, PVP, Voltammetry, DFT, XPS, Surface Reactivity
Additional Information:	Pdf uploaded in accordance with publisher's policy at http://www.sherpa.ac.uk/romeo/issn/1932-7447/ (accessed 29/03/2016)
Publisher:	ACS Publications
ISSN:	1932-7447
Funders:	Natural Science Foundation of China, EPSRC
Date of First Compliant Deposit:	30 March 2016
Date of Acceptance:	23 March 2016
Last Modified:	06 Jan 2024 04:57
URI:	https://orca.cardiff.ac.uk/id/eprint/88262

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