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Isopolytungstate Adsorption on Platinum: Manifestations of Underpotential Deposition Full article

Общее Language: Английский, Genre: Full article,
Status: Published, Source type: Original
Journal Electrocatalysis
ISSN: 1868-2529 , E-ISSN: 1868-5994
Output data Year: 2012, Volume: 3, Number: 3-4, Pages: 230 - 237 Pages count : 8 DOI: 10.1007/s12678-012-0114-1
Tags Coadsorption, Keggin structure, Metatungstate, Platinum, Underpotential deposition
Authors Cherstiouk Olga V. 1 , Simonov Alexander N. 1 , Tsirlina Galina A. 2
Affiliations
1 Boreskov Institute of Catalysis, Siberian Division of the Russian Academy of Sciences, Prospekt Ak. Lavrentieva 5, Novosibirsk 630090, Russia
2 Department of Electrochemistry, Moscow University, Leninskie Gory, 3, str.1, Moscow 199991, Russia

Funding (1)

1 Russian Foundation for Basic Research 11-03-00902

Abstract: Metatungstate isopolyanion adsorption on smooth polycrystalline Pt and carbon-supported dispersed platinum in sulfuric acid medium is studied by cyclic voltammetry. Manifestations of both reversible and irreversible adsorption are found, with the features typical for heteropolytungstates of the same Keggin structure. When (NH4)6H2W12O40 is added to sulfuric acid solution, H underpotential deposition (UPD) charge starts to redistribute: it decreases at high hydrogen coverage but increases at higher potentials, with appearance of additional reversible redox feature in “double layer region.” The total charge value in diluted metatungstate solutions remains the same as for pure Pt. However, this value decreases with metatungstate concentration. At any fixed (NH4)6H2W12O40 concentration, the total charges in the hydrogen region are practically the same in 0.1 and 0.5 M sulfuric acid. Strongly bonded metatungstate species can be kept at the surface after the transfer to supporting solution. These irreversibly adsorbed species are redox-inactive and demonstrate stronger suppression of H UPD. Excursion to oxygen adsorption region does not result in complete desorption, but redistribution of charge takes place again. Our observations can be assigned (by analogy with Keggin anions adsorption on Au and Ag) to slow adsorbate–metal bonding, with subsequent increase of the number of bonded oxygen atoms. General trends are qualitatively the same for both Pt materials, but dispersed Pt on glassy carbon favors irreversible adsorption. The data confirm that adsorbed metatungstate can undergo reversible reduction at potentials more positive than the equilibrium potential of its first W(V/VI) redox transition (molecular UPD). Comparative electrocatalytic tests are presented for nitrate electroreduction on bare Pt, Pt modified with irreversibly adsorbed metatungstate, and Pt in metatungstate solution. The latter system, containing both forms of tungstate adsorbate, demonstrates high steady-state electrocatalytic activity at potentials below ca. 0.1 V reversible hydrogen electrode (RHE).
Cite: Cherstiouk O.V. , Simonov A.N. , Tsirlina G.A.
Isopolytungstate Adsorption on Platinum: Manifestations of Underpotential Deposition
Electrocatalysis. 2012. V.3. N3-4. P.230 - 237. DOI: 10.1007/s12678-012-0114-1 publication_identifier_short.wos_identifier_type publication_identifier_short.scopus_identifier_type publication_identifier_short.rinz_identifier_type
Dates:
Published online: Oct 6, 2012
Published print: Dec 1, 2012
Identifiers:
publication_identifier.wos_identifier_type WOS:000312634100010
publication_identifier.scopus_identifier_type 2-s2.0-84871313164
publication_identifier.rinz_identifier_type 20488083
publication_identifier.accession_number_identifier_type 2012:1846853
publication_identifier.chemical_accession_number_identifier_type 159:759101
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