Influence of the Electrode and Chaotropicity of the Electrolyte on the Oscillatory Behavior of the Electrocatalytic Oxidation of SO2

SO2 oxidation has been proposed as an alternative pathway for the electrochemical generation of H2 because it requires lower potentials than water splitting and at the same time consumes an atmospheric pollutant. Theoretical predictions suggest that gold and platinum are the most active catalysts for this reaction. This work presents experimental evidence that, contrary to the predictions, SO2 oxidation starts at less positive potentials on Au electrodes (ca. 0.60 V (vs RHE)) than on Pt. It is found further that the observed current densities on Au are one order of magnitude higher than on Pt. In addition, the SO2 oxidation mechanism depends on the chemical nature of the electrolyte used: A kosmotropic anion (HSO4–) results in lower currents than a chaotropic one (ClO4–), and the latter displays oscillatory reaction rates under both potentiostatic and galvanostatic regimes.

[1]  R. J. Kriek,et al.  The Effect of Rapid Thermal Annealing on Sputtered Pt and Pt3Pd2 Thin Film Electrocatalysts for Aqueous SO2 Electro-Oxidation , 2015, Electrocatalysis.

[2]  J. Parrondo,et al.  Evaluation of Polycrystalline Platinum and Rhodium Surfaces for the Electro-Oxidation of Aqueous Sulfur Dioxide , 2015, Electrocatalysis.

[3]  M. Cabral,et al.  Oscillatory electro-oxidation of thiosulfate on gold , 2014 .

[4]  J. Rossmeisl,et al.  H(2) production through electro-oxidation of SO(2): identifying the fundamental limitations. , 2014, Physical chemistry chemical physics : PCCP.

[5]  W. Maier,et al.  Search for new catalysts for the oxidation of SO₂. , 2013, ACS combinatorial science.

[6]  Y. Demirel.  Thermodynamic Analysis , 2013 .

[7]  J. Rossmeisl,et al.  SO2 - An indirect source of energy , 2013 .

[8]  A. Horváth,et al.  Bisulfite-driven autocatalysis in the bromate-thiosulfate reaction in a slightly acidic medium. , 2012, Inorganic Chemistry.

[9]  Robert G. Kelly,et al.  Electrochemical Characterization of the Surface Area of Nanoporous Gold Films , 2012 .

[10]  S. Donne,et al.  Electrochemical Oxidation of Aqueous Sulfur Dioxide II. Comparative Studies on Platinum and Gold Electrodes , 2012 .

[11]  S. Donne,et al.  Observed electrochemical oscillations during the oxidation of aqueous sulfur dioxide on a sulfur modified platinum electrode , 2011 .

[12]  S. Donne,et al.  The Electrochemical Oxidation of Aqueous Sulfur Dioxide I. Experimental Parameter Influences on Electrode Behavior , 2010 .

[13]  I. Epstein,et al.  Temperature-induced bifurcations in the Cu(II)-catalyzed and catalyst-free hydrogen peroxide-thiosulfate oscillating reaction. , 2010, The journal of physical chemistry. A.

[14]  S. Donne,et al.  The electrochemical oxidation of aqueous sulfur dioxide: a critical review of work with respect to the hybrid sulfur cycle , 2010 .

[15]  J. Weidner,et al.  A thermodynamic analysis of the SO2/H2SO4 system in SO2-depolarized electrolysis , 2009 .

[16]  M. Gorensek,et al.  Hybrid sulfur flowsheets using PEM electrolysis and a bayonet decomposition reactor , 2009 .

[17]  D. Hobbs,et al.  Catalyst evaluation for a sulfur dioxide-depolarized electrolyzer , 2007 .

[18]  Jichang Wang,et al.  Dynamic instabilities and mechanism of the electrochemical oxidation of thiosulfate. , 2006, Journal of Physical Chemistry B.

[19]  S. Brankovic,et al.  Metal monolayer deposition by replacement of metal adlayers on electrode surfaces , 2001 .

[20]  J. Vázquez,et al.  Electrochemical behaviour of aqueous SO2 at polycrystalline gold electrodes in acidic media. A voltammetric and in-situ vibrational study. Part II. Oxidation of SO2 on bare and sulphur-modified electrodes , 2001 .

[21]  J. Vázquez,et al.  Electrochemical behaviour of aqueous SO2 at polycrystalline gold electrodes in acidic media: a voltammetric and in situ vibrational study: Part 1. Reduction of SO2: deposition of monomeric and polymeric sulphur , 2000 .

[22]  M. Eiswirth,et al.  Mechanistic classification of electrochemical oscillators — an operational experimental strategy , 1999 .

[23]  M. Koper.  Non-linear phenomena in electrochemical systems , 1998 .

[24]  Ji-won Lee,et al.  Electrochemical sulphur dioxide oxidation with platinum-aluminum electrocatalysts , 1995 .

[25]  A. Wiȩckowski,et al.  Investigations of SO42− adsorption at the Au(111) electrode by chronocoulometry and radiochemistry , 1994 .

[26]  Z. Samec,et al.  Study of the oxidation of SO2 dissolved in 0·5 M H2SO4 on a gold electrode—II. A rotating disc electrode , 1975 .

[27]  Z. Samec,et al.  Study of the oxidation of SO2 dissolved in 0·5 M H2SO4 on a gold electrode—I stationary electrode , 1975 .