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Corresponding Author

Zou Shouzhong(zous@muohio.edu)

Abstract

Adsorbed sulfur is commonly considered as a reaction poison. However, small amounts of sulfur on platinum significantly increase the surface reactivity toward carbon monoxide (CO) electrooxidation. For the solution CO oxidation, the onset potential was shifted up to over 300 mV negative to that on S-free surface, and the extent of the negative potential shift increases with the sulfur coverage (Xs) up to about 0.6. The enhanced CO oxidation also depends on the solution pH. For the adsorbed CO, at low sulfur coverages (Xs < 0.3), the oxidation peak potential is about 40 mV negative to that of the corresponding clean Pt. However, at higher coverages, the peak potential is about 30 mV more positive. Surface-enhanced Raman spectra show that the adsorption of sulfur significantly redshifts the Pt-CO stretching frequency. These observations are explained by the weakening of the Pt-CO bond and the hindrance of CO diffusion by Sads.

Graphical Abstract

Keywords

electrooxidation, adsorbed sulfur, carbon monoxide, platinum, surface-enhanced Raman spectroscopy

Publication Date

2012-12-28

Online Available Date

2012-08-29

Revised Date

2012-08-09

Received Date

2012-06-23

References

[1] Somorjai G A. Introduction to surface chemistry and catalysis[M]. New York, Wiley: 1994.

[2] Wimmer E, Fu C L, Freeman A. J. Catalytic promotion and poisoning - all-electron local-density-functional theory of CO on Ni(001) surfaces coadsorbed with K or S[J]. Physical Review Letters.1985, 55 (23): 2618-2621.

[3] Feibelman P J, Hamann D R. Modification of transition metal electronic structure by P, S, Cl, and Li Adatoms[J]. Surface Science.1985, 149: 48-66.

[4] Garfunkel E L, Farias M H, Somorjai G A. The modification of benzene and carbon-monoxide adsorption on Pt(111) by the coadsorption of potassium or sulfur[J]. Journal of the American Chemical Society, 1985, 107 (2): 349-353.

[5] Gdowski G E, Madix R J. The effect of sulfur on CO adsorption desorption on Pt(S)- 9(111)X(100)[J]. Surface Science.1982, 115(3): 524-540.

[6] Jorgensen S W, Madix R J. Steric and electronic effects of sulfur on CO adsorbed on Pd(100)[J]. Surface Science, 1985, 163 (1): 19-38.

[7] Kiskinova M, Szabo A, Yates J T. CO adsorption on Pt(111) modified with sulfur. Journal of Chemical Physics[J].1988, 89 (12): 7599-7608.

[8] Lanzillotto A M, Bernasek S L. The effect of the sulfur induced reconstruction of the Pt(S)- 6(111) X (100) surface on CO adsorption[J]. Surface Science, 1986, 175(1): 45-54.

[9] Protopopoff E, Marcus P. Coadsorption of sulphur and hydrogen on Pt(111) studied by radiotracer and electrochemical techniques[J]. Surface Science, 1986, 169: L237-L244.

[10] Protopopoff E, Marcus P. Effect of chemisorbed sulfur on the electrochemical hydrogen adsorption and recombination reactions on Pt (111)[J]. Journal of Vacuum Science and Technology A. 1987, 5 (4): 944-947.

[11] Protopopoff E, Marcus P. Potential-pH diagrams for sulfur and hydroxyl adsorbed on copper surfaces in water containing sulfides, sulfites or thiosulfates[J]. Corrosion Science, 2003, 45(6): 1191-1201.

[12] Sung Y E, Chrzanowski W, Wieckowski A, et al. Coverage evolution of sulfur on Pt(111) electrodes: From compressed overlayers to well-defined islands[J]. Electrochimica Acta, 1998, 44(6/7): 1019-1030.

[13] Sung Y E, Chrzanowski W, Zolfaghari, A, et al. Structure of chemisorbed sulfur on a Pt(111) electrode[J]. Journal of the American Chemical Society, 1997, 119(1): 194-200.

[14] Thomas V D, Schwank J W, Gland J L. Carbon monoxide desorption from platinum chemically modified by sulfur[J]. Surface Science, 2000, 464(2/3): 153-164.

[15] Zolfaghari A, Jerkiewicz G, Chrzanowski W, et al. Energetics of the underpotential deposition of hydrogen on platinum electrodes ii.presence of coadsorbed sulfur[J]. Journal of the Electrochemical Society, 1999, 146(11): 4158-4165.

[16] Rodriguez J A, Chaturvedi S, Jirsak T. The bonding of sulfur to Pd surfaces: Photoemission and molecular orbital studies[J]. Chemical Physics Letters, 1998, 296(3/4): 421-428.

[17] Rodriguez J A, Dvorak J, Jirsak T, et al. Coverage effects and the nature of the metal-sulfur bond in S/Au(111): High resolution photoemission and density-functional studies[J]. Journal of the American Chemical Society, 2003, 125(1): 276-285.

[18] Rodriguez J A, Kuhn M, Hrbeck J. The bonding of sulfur to a Pt(111) surface: Photoemission and molecular orbital studies[J]. Chemical Physics Letters, 1996, 251(1/2): 13-19.

[19] Zaera F, Salmeron M. Coadsorption of sulfur and carbon monoxide on platinum single crystal surfaces studied by scanning tunneling microscopy[J]. Langmuir, 1998, 14(6): 1312-1319.

[20] Binder H, Kohling A, Sandstede G. Acceleration by adsorbed sulphur and selenium of the electrochemical oxidation of formic acid on platinum catalyst[J]. Nature, 1967, 214: 268-269.

[21] Binder H, Kohling A, Sandstede G. The anodic oxidation of carbon monoxide and formic acid on platinum covered with sulfur. In Fuel Cell Systems II, Baker B S, Ed[M]. American Chemical Society: Washington, D.C., 1969.

[22] Contractor A Q, Lal H. Formic acid oxidation at platinized platinum electrodes part V. A further study of catalytic effect of pre-adsorbed sulfur[J]. Journal of Electroanalytical Chemistry, 1979, 103(1): 103-117.

[23] Watanabe M, Motoo S. Electrocatalysis by Ad-atoms part XVI enhancement of carbon monoxide oxidation on platinum electrode in acid solution by the VIth Ad-atoms[J]. Journal of Electroanalytical Chemistry, 1985, 194(2): 275-278.

[24] Watanabe M, Motoo S. Electrocatalysis by Ad-atoms part XV. Enhancement of co oxidation on platinum by the electronegativity of Ad-atoms[J]. Journal of Electroanalytical Chemistry, 1985, 194: 261-274.

[25] Loucka T. Adsorption and oxidation of organic compounds on a platinum electrode partly covered by adsorbed sulphur[J]. Journal of Electroanalytical Chemistry, 1972, 36: 355.

[26] Park I S, Chen D J, Atienza D O. Enhanced CO monolayer electro-oxidation reaction on sulfide-adsorbed Pt nanoparticles: A combined electrochemical and in situ ATR-SEIRAS spectroscopic study[J]. Catalysis today, 2012, http://dx.doi.org/10.1016/j.cattod.2012.05.045.

[27] Weaver M J, Zou S. Z, Chan H Y H. The new interfacial ubiquity of surface-enhanced raman spectroscopy[J]. Analytical Chemistry, 2000, 72(1): 38A-47A.

[28] Zou S Z, Weaver M J. Surface-enhanced Raman scattering an uniform transition metal films: Toward a versatile adsorbate vibrational strategy for solid-nonvacuum interfaces?[J]. Analytical Chemistry, 1998, 70(11): 2387-2395.

[29] Zou S Z, Williams C T, Chen E K Y, et al. Probing molecular vibrations at catalytically significant interfaces: A new ubiquity of surface-enhanced Raman scattering[J]. Journal of the American Chemical Society, 1998, 120(15): 3811-3812.

[30] Zou S Z, Williams C T, Chen E K Y, et al. Surface-enhanced Raman scattering as a ubiquitous vibrational probe of transition-metal interfaces: Benzene and related chemisorbates on palladium and rhodium in aqueous solution[J]. Journal of Physical Chemistry B, 1998, 102(45): 9039-9049.

[31] Gao P, Gosztola D, Leung L W H, et al. Surface-enhanced Raman-scattering at gold electrodes - dependence on electrochemical pretreatment conditions and comparisons with silver[J]. Journal of Electroanalytical Chemistry, 1987, 233(1/2): 211-222.

[32] Mrozek M F, Xie Y, Weaver M J. Surface-enhanced Raman scattering on uniform platinum-group overlayers: Preparation by redox replacement of underpotential-deposited metals on gold[J]. Analytical Chemistry, 2001, 73(24): 5953-5960.

[33] Park I S, Xu B, Atienza D O, et al. Chemical state of adsorbed sulfur on Pt nanoparticles[J]. ChemPhysChem, 2011, 12(4): 747-752.

[34] Batina N, McCargar J W, Salaita G N, et al. Structure and composition of Pt(111) and Pt(100) surfaces as a function of electrode potential in aqueous sulfide solutions[J]. Langmuir, 1989, 5(1): 123-128.

[35] Foresti M L, Innocenti M, Forni F, et al. Electrosorption valency and partial charge transfer in halide and sulfide adsorption on Ag(111)[J]. Langmuir, 2001, 14(24): 7008-7016.

[36] Yang, H. Z.; Zou, S. Z., in preparation.

[37] Markovic N M, Lucas C A, Rodes A, et al. Surface electrochemistry of CO on Pt(111): Anion effects[J]. Surface Science, 2002, 499(2/3): L149-L158.

[38] Lebedeva N P, Koper M T M, Feliu J M. Mechanism and kinetics of the electrochemical CO adlayer oxidation on Pt(111)[J]. Journal of Electroanalytical Chemistry, 2002, 524: 242-521.

[39] Lebedeva N P, Koper M T M, Feliu J M, et al. Role of crystalline defects in electrocatalysis: Mechanism and kinetics of CO adlayer oxidation on stepped platinum electrodes[J]. Journal of Physical Chemistry B, 2002, 106(50): 12938-12947.

[40] Lebedeva N P, Koper M T M, Herrero E, et al. Cooxidation on stepped Pt[n(111) x (111)] electrodes[J]. Journal of Electroanalytical Chemistry, 2000, 487(1): 37-44.

[41] Zou S Z, Weaver M J. Potential-dependent metal-adsorbate stretching frequencies for carbon monoxide on transition-metal electrodes: Chemical bonding versus electrostatic field effects[J]. Journal of Physical Chemistry.1996, 100(10): 4237-4242.
[42] Xu B, Park I S, Li Y, et al. An in situ SERS investigation of the chemical states of sulfur species adsorbed onto Pt from different sulfur sources[J]. Journal of Electroanalytical Chemistry, 2011, 662(1): 52-56.
[43] Mrozek M F, Weaver M J. Periodic trends in monoatomic chemisorbate bonding on platinum-group and other noble-metal electrodes as probed by surface-enhanced raman spectroscopy[J]. Journal of the American Chemical Society, 2000, 122(1): 150-155.
[44] Gao X P, Zhang Y, Weaver M J. Adsorption and electrooxidative pathways for sulfide on gold as probed by real-time surface-enhanced raman-spectroscopy[J]. Langmuir, 1992, 8(2): 668-672.
[45] Koper M T M, van Santen R A, Wasileski S A, et al. Field-dependent chemisorption of carbon monoxide and nitric oxide on platinum-group (111) surfaces: Quantum chemical calculations compared with infrared spectroscopy at electrochemical and vacuum-based interfaces[J]. Journal of Chemical Physics, 2000, 113(10), 4392-4407.
[46] Tang C, Zou S, Severson M W, et al. Coverage-dependent infrared spectroscopy of carbon monoxide on Iridium(111) in aqueous solution: A benchmark comparison between chemisorption in ordered electrochemical and ultrahigh-vacuum environments[J]. Journal of Physical Chemistry B, 1998, 102 (44): 8796-8806.
[47] Tang C, Zou S Z, Severson M W, et al. Infrared spectroscopy of mixed nitric-oxide-carbon-monoxide adlayers on ordered iridium(111) in aqueous solution: A model study of coadsorbate vibrational interactions[J]. Journal of Physical Chemistry B.1998, 102 (43): 8546-8556.
[48] Korzeniewski C, Kardash D. Use of a dynamic monte carlo simulation in the study of nucleation-and-growth models for CO electrochemical oxidation[J]. Journal of Physical Chemistry B, 2001, 105(37): 8663-8671.
[49] Love B, Lipkowski J. ACS Symp. Ser.[M]. 1988; Vol. 378, p 484-496.
[50] Koper M T M. Combining experiment and theory for understanding electrocatalysis[J]. Journal of Electroanalytical Chemistry, 2005, 574(2), 375-386.
[51] Bonzel H P, Ku R. Adsorbate interactions on a Pt(110) surface. I. Sulfur and carbon monoxide[J]. Journal of Chemical Physics, 1973, 58(10): 4617-4623.
[52] Markovic N M, Grgur B N, Lucas C A, et al. Electrooxidation of CO and H2/CO mixtures on Pt(111) in acid solutions[J]. Journal of Physical Chemistry B, 1999, 103(3): 487-495.
[53] Batteas J D, Dunphy J C, Somorjai G A, et al. Coadsorbate induced reconstruction of a stepped Pt(111) surface by sulfur and CO: A novel surface restructuring mechanism observed by scanning tunneling microscopy[J]. Physical Review Letters, 1996, 77(3), 534-537.
[54] Dunphy J C, McIntyre B J, Gomez J, et al. Coadsorbate induced compression of sulfur overlayers on Re(0001) and Pt(111) by CO[J]. Journal of Chemical Physics.1994, 100(8): 6092-6097.
[55] McIntyre B J, Salmeron M, Somorjai G A. An in situ STM determination of a kinetic pathway for the coadsorbate-induced compression of sulfur by CO on Pt(111)[J]. Surface Science, 1995, 323: 189-197.
[56] Xiao X D, Xie Y, Jakobsen C, et al. Impurity effect on surface diffusion: CO/S/Ni (110)[J]. Physical Review Letters, 1995, 74(19): 3860-3863.
[57] Saravanana C, Markovic N M, Head-Gordon M, et al. Stripping and bulk CO electro-oxidation at the Pt-electrode interface: Dynamic Monte Carlo simulations[J]. Journal of Chemical Physics, 2001, 114(14): 6404-6412.
[58] Xia X H, Vielstich W. Enhanced oxidation of carbon monoxide on platinum in HClO4 Via Interaction with Acetonitrile[J]. Electrochimica Acta, 1994, 39(1): 13-21.

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