Mechanisms for Ethanol Electrooxidation on Pt(111) and Adsorption Bond Strengths Defining an Ideal Catalyst

Asiri, Haleema Aied; Anderson, Alfred B.

doi:10.1149/2.0781501jes

Cited by 40 publications

(57 citation statements)

References 33 publications

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“…This is because they are ideal candidates for use in portable devices and are excellent alternatives that offer clean energy [1−3]. As we all know, Pt is the best catalyst of all pure metals for the PEMFCs [4]. However, it is hindered by the limited reserves, high cost, and its poor resistance to CO poisoning despite the high activity [5].…”

Section: Introductionmentioning

confidence: 99%

One-step synthesis of the PdPt bimetallic nanodendrites with controllable composition for methanol oxidation reaction

Zhang

Chen

et al. 2018

Sci. China Mater.

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This paper demonstrates a one-pot approach to produce highly dispersed dendritic palladium-platinum bimetallic nanoparticles (NPs) with small particle size, tunable composition and high catalytic activity. Herein, the PdPt bimetallic NPs have been obtained using bayberry tannin (BT) as both the reducing agent and surfactant. Additionally, the PdPt bimetallic NPs with different Pd/Pt atomic ratios can be prepared by just varying the amounts of the Pd and Pt precursors. Most importantly, the as-prepared Pd 52 Pt 48 catalyst exhibits the optimal catalytic activities compared with the other compositional PdPt NPs (Pd 82 Pt 18 , Pd 69 Pt 31 , and Pd 36 Pt 64 ) and commercial Pt/C (20 wt.%) catalyst for the methanol oxidation reaction (MOR). Meanwhile, Pd 52 Pt 48 also shows better CO tolerance, which can be attributed to the unique dendritic structure and the synergistic effect between Pd and Pt. With evident advantages of the facile preparation and enhanced catalytic performance, it holds great promise as a high-performance catalyst for electrochemical energy conversion.

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Section: Introductionmentioning

confidence: 99%

One-step synthesis of the PdPt bimetallic nanodendrites with controllable composition for methanol oxidation reaction

Zhang

Chen

et al. 2018

Sci. China Mater.

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“…Ethanol oxidation reaction (EOR) is a complex anodic process, which involves dissociation of preadsorbed ethanol molecules to produce surface-adsorbed carbon monoxide (CO ad ) species and further oxidation of C 2 H 5 OH to form (apart from numerous intermediates and by-products) two major chemicals, namely acetaldehyde and acetic acid (Pathway I: 4e − ). In fact, most of these products might become adsorbed on the catalyst surface, and thus, quantitative cleavage of the C-C bond (in order to finally generate CO 2 Pathway II: 12e − ) in an ethanol molecule constitutes a key technical problem [1][2][3][4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Enhancement of Ethanol Oxidation Reaction on Pt (PtSn)-Activated Nickel Foam Through In situ Formation of Nickel Oxy-Hydroxide Layer

Pierożyński

Mikołajczyk

2017

Electrocatalysis

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The present paper reports on a significant enhancement of ethanol oxidation reaction (EOR), investigated on Pt and PtSn-modified nickel foam electrodes, realized via in situ formation of surface nickel oxy-hydroxide layer in 0.1 M NaOH solution. In the presence of ethanol in electrolyte, adsorbed C 2 H 5 OH molecules (and/or its oxidation intermediates) prevent Pt (PtSn) sites from their extensive dissolution upon prolonged surface electrooxidation of Ni foam electrode. The above was elucidated through cyclic voltammetry examinations and a.c. impedance-derived charge transfer resistance parameter values. Surface topography and the presence of catalytic additives were revealed from the combined scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX) analyses.

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“…1 In Ref. 1 this was done by taking known standard Gibbs reaction energies for solution phase reactions and perturbing them by the adsorption bond strengths of R-H and R to give Gibbs energies for the reactions on the surface.…”

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confidence: 99%

“…For this, a self-consistent density functional theory (DFT) which includes the electrolyte and its polarization by the aqueous molecules 2 was used in Ref. 1. The details of the DFT will be outlined later in this paper.…”

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Reaction Energy for an Electrode Surface Atom Inserting into an R-H Bond and Its Dependence on Electrode Potential: Application to Pt(111)

Anderson

Zhao

2015

J. Electrochem. Soc.

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Formulas are derived for calculating the dissociation energies for adsorbed R-H forming adsorbed R and H on Pt(111) electrodes from the reversible potentials for oxidizing R-H ads to R ads + H + aq . Here R is a radical CH x O y · such as CH 3 · , OH · and HOĊHCH 3 . When the oxidation reversible potentials lie potential range where in the under potential deposited H ads is present on the surface, which is zero to approximately 0.35 V, on the standard hydrogen scale, the R-H bond strengths are predicted to be zero. For adsorbed molecules with reversible potentials above 0.35 V, the dissociation energy increases linearly as the difference between the reversible potential and 0.35 V and for molecules with reversible potentials below zero volts the dissociation energy becomes negative. Applications to reversible potentials for water and ethanol redox steps show that H ads does not play a role in oxygen reduction to water and for only one of the steps in ethanol oxidation is dissociation forming H ads excluded. For the other ethanol oxidation steps there is currently insufficient information to decide whether R-H dissociates prior to oxidation. Electrochemistry is not ordinarily expected to be a tool for measuring bond strengths. In this paper it is shown how to determine R-H bond strengths in adsorbed molecules, such as CH 4ads , H 2 O ads , and HOCH 2 CH 3ads , from standard reversible potentials for oxidation of the bonds to R ads + H + aq + e − . We call this the oxidation into solution reaction. The electrode treated in this paper is platinum, and the close-packed (111) surface is chosen for modeling.The standard reversible potentials employed in this paper were determined previously.1 In Ref. 1 this was done by taking known standard Gibbs reaction energies for solution phase reactions and perturbing them by the adsorption bond strengths of R-H and R to give Gibbs energies for the reactions on the surface. Reversible potentials for the surface reactions were then calculated using these surface reaction Gibbs energies. Except for O-H and HO-H bonds, standard reversible potentials for oxidizing R-H bonds in aqueous molecules treated in this paper are unavailable from experiments. This makes it necessary to calculate the missing values. Because reversible potentials are functions of reaction Gibbs energies, predicting them demands accurate calculations of the Gibbs free energies of the reactants and products. For this, a self-consistent density functional theory (DFT) which includes the electrolyte and its polarization by the aqueous molecules 2 was used in Ref. 1. The details of the DFT will be outlined later in this paper.The R-H oxidation reactions addressed in this paper occur as steps during electrooxidation of ethanol on the anode of a fuel cell. The Pt(111) surface is chosen because it has broad, well-defined under potential deposited (UPD) H ads and double layer potential ranges and because it is well-studied by electrochemists. Knowing the reversible potentials for all the conceivable oxidation into solut...

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Mechanisms for Ethanol Electrooxidation on Pt(111) and Adsorption Bond Strengths Defining an Ideal Catalyst

Cited by 40 publications

References 33 publications

One-step synthesis of the PdPt bimetallic nanodendrites with controllable composition for methanol oxidation reaction

One-step synthesis of the PdPt bimetallic nanodendrites with controllable composition for methanol oxidation reaction

Enhancement of Ethanol Oxidation Reaction on Pt (PtSn)-Activated Nickel Foam Through In situ Formation of Nickel Oxy-Hydroxide Layer

Reaction Energy for an Electrode Surface Atom Inserting into an R-H Bond and Its Dependence on Electrode Potential: Application to Pt(111)

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