Potential oscillations during electro-oxidation of ethanol on platinum in alkaline media: The role of surface sites

Abstract

Potential oscillations during electro-oxidation of ethanol on platinum in alkaline media: The role of surface sites, Electrochemistry Communications (2016Communications ( ), doi: 10.1016Communications ( /j.elecom.2016 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT AbstractThe electro-oxidation of small organic molecules is one of the major areas of interest in electrocatalysis due to its potential use in energy conversion. Instabilities in alkaline solution, particularly in comparison with kinetic properties in a conventional regime, are rarely reported in the literature, despite the fact that the catalytic activity is higher in this medium and the onset potential is shifted to lower values compared to acidic media.Ethanol oxidation on polycrystalline platinum exhibits oscillations under galvanostatic control. As the reaction is structure-sensitive, it is possible to study the contribution of the three platinum basal planes to the complex kinetics. We found that Pt(100) has the major influence in the overall non-linear kinetics of ethanol electro-oxidation on Pt(poly), possibly because it has the highest formation and accumulation rate of CO ads . Based on the differences observed in the galvanostatic transients on Pt(poly), Pt(110) and Pt(100), and the absence of this behaviour on Pt(111), it is possible to infer that surface sites strongly influence the kinetic scenario during the ethanol oxidation reaction.

Role of Noncovalent Interactions on the Electrocatalytic Oxidation of Ethanol in Alkali Metal Hydroxide Solutions

“…As a green and efficient energy conversion device, direct ethanol fuel cells (DEFCs) have drawn extensive research attention in the last 2 decades. However, the electrochemical performances of the DEFCs are not satisfactory for industrial applications, , mainly due to the sluggish Faraday efficiency of ethanol electro-oxidation reactions (EORs). − In this regard, many studies have been executed to reveal the ethanol electro-oxidation reaction mechanisms. − …”

Elucidating the alkaline oxygen evolution reaction mechanism on platinum

“…6,7 In particular, Pt has been used as a model system to provide surface chemical and structural transformation insights under various (electro)chemical reaction environments. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] Ultimately, the scope of these studies is to expedite the development of novel and cost-effective catalysts with tailored physical/chemical properties, capable of achieving, if not surpassing, the Pt electrocatalytic performance. 8,[24][25][26][27] Previous studies have been conducted to indentify the role of Pt oxides in the oxygen evolution reaction pathway (also known as oxygen discharge).…”

“…Such an increase is oen attributed to an increase of the surface oxide layer thickness and Pt dissolution. 13,[15][16][17][18][19][20][21][22][23][24][25][26]29 In alkaline media, the reversible binding of a hydroxide ion (OH À ) coupled to a one electron oxidation is thought to precede the removal of one proton and one electron to form surface oxide species. 30 This hypothesis has been mostly supported so far by surface structure and chemical characterizations far from operando conditions, 6,31,32 thereby limiting an unambiguous investigation of the role of Pt oxides in the oxygen evolution catalytic cycle.…”

Electrochemical Oscillations (Named Oscillations H and K) during H2O2 Reduction on Pt Electrodes Induced by a Local pH Increase at the Electrode Surface

“…The study of oscillatory instability has also received attention because it provides a deeper understanding of complex electrochemical reactions, such as the oxidation of C1 organic molecules 8,9 and intermolecular interactions between electroactive species and adsorbates. [10][11][12][13] Interestingly, these studies have even provided valuable information that has led to improvements in the discharge capacity of lithium-oxygen batteries. 14 The N-shaped negative differential resistance (N-NDR) plays a crucial role in the positive feedback mechanism for typical electrochemical oscillators: the N-NDR oscillator and the "hidden" N-NDR (HN-NDR) oscillator.…”