Phase Transitions Involving Dissociated States of Water at the Electrochemical Ni(111)/H2O Interface

Taylor, Caroline; Kelly, Robert G.; Neurock, Matthew

doi:10.2172/882552

Cited by 8 publications

(9 citation statements)

References 37 publications

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“…This size of the surface may not be large enough to fully capture the influence of coadsorbed water which can act to stabilize the intermediates and products. The approach taken by Filhol was later extended by Taylor et al [44] over Cu(111), and used to examine a broader range of potentials. A number of these issues were removed by ultimately using a much larger 3 9 3 unit cell as well as external reservoirs to solvate the H + /OH -species that form.…”

Section: Methodsmentioning

confidence: 99%

“…The results of this study showed that, as the potential was increased from the potential of zero charge, water was activated to form surface hydroxide intermediates followed by a surface oxide layer that formed at further increases of the potential. At high enough potentials, the adsorbed oxygen and the surface Cu atoms exchange places ultimately leading to the dissolution of solvated Cu 2+ ions and a passivating Cu 2 O overlayer atop the Cu(111) surface [44].…”

Section: Methodsmentioning

confidence: 99%

“…In this way the pH is maintained at a constant neutral value throughout the simulations, and variations in pH can be considered by simply adding NRT ln[H + ] to lN. We have applied this approach to the activation of water over different model metal substrates including Cu(111) [44], Ni(111) [32], and Pt(111) [24]. Figure 4a, b, for example, presents the regions of temperature/pH phase-space over which H 2 O and its dissociation products are stable over the ideal (111) surfaces of Cu and Ni respectively.…”

Section: Methodsmentioning

confidence: 99%

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First Principles Analysis of the Electrocatalytic Oxidation of Methanol and Carbon Monoxide

2007

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The strong drive to commercialize fuel cells for portable as well as transportation power sources has led to the tremendous growth in fundamental research aimed at elucidating the catalytic paths and kinetics that govern the electrode performance of proton exchange membrane (PEM) fuel cells. Advances in theory over the past decade coupled with the exponential increases in computational speed and memory have enabled theory to become an invaluable partner in elucidating the surface chemistry that controls different catalytic systems. Despite the significant advances in modeling vapor-phase catalytic systems, the widespread use of first principle theoretical calculations in the analysis of electrocatalytic systems has been rather limited due to the complex electrochemical environment. Herein, we describe the development and application of a first-principles-based approach termed the double reference method that can be used to simulate chemistry at an electrified interface. The simulations mimic the half-cell analysis that is currently used to evaluate electrochemical systems experimentally where the potential is set via an external potentiostat. We use this approach to simulate the potential dependence of elementary reaction energies and activation barriers for different electrocatalytic reactions important for the anode of the direct methanol fuel cell. More specifically we examine the potential-dependence for the activation of water and the oxidation of methanol and CO over model Pt and Pt alloy surfaces. The insights from these model systems are subsequently used to test alternative compositions for the development of improved catalytic materials for the anode of the direct methanol fuel cell.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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First Principles Analysis of the Electrocatalytic Oxidation of Methanol and Carbon Monoxide

2007

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“…Accordingly, many studies are progressively revealing the atomic-level details of the electrode reactions at water electrolysis cells. [122][123][124][125] Early electrolysis cells were about 60-75% efficient. However, the current small-scale, best-practice figure is close to 80-85%, with larger units being a little less efficient (ca.…”

Section: Future Trendsmentioning

confidence: 99%

Hydrogen production by alkaline water electrolysis

Santos¹,

Sequeira²,

Figueiredo³

2013

Quím. Nova

370

226

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Recebido em 13/12/12; aceito em 28/5/13; publicado na web em 17/7/13Water electrolysis is one of the simplest methods used for hydrogen production. It has the advantage of being able to produce hydrogen using only renewable energy. To expand the use of water electrolysis, it is mandatory to reduce energy consumption, cost, and maintenance of current electrolyzers, and, on the other hand, to increase their efficiency, durability, and safety. In this study, modern technologies for hydrogen production by water electrolysis have been investigated. In this article, the electrochemical fundamentals of alkaline water electrolysis are explained and the main process constraints (e.g., electrical, reaction, and transport) are analyzed. The historical background of water electrolysis is described, different technologies are compared, and main research needs for the development of water electrolysis technologies are discussed.

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“…In this work, we present a kinetic study of the HOR/HER on Ni electrodes in the pH range from 12 to 14. Since the HOR/HER activity of Ni is rather low due to the strong hydrogen binding to the surface, it is usually enhanced either by partially oxidizing Ni surfaces or by combining Ni with other non‐noble transition metals such as Mo, Cr, Co or Cu . Hence, to have a better understanding of the pH dependence, along with metallic Ni, in this work we also explore a partially oxidized Ni as well as a NiCu/C electrode.…”

Section: Introductionmentioning

confidence: 99%

Influence of the NaOH Concentration on the Hydrogen Electrode Reaction Kinetics of Ni and NiCu Electrodes

et al. 2020

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Nickel is a promising electrocatalyst for hydrogen electrode reactions in alkaline media. Its electrocatalytic activity for hydrogen oxidation and evolution reactions can be enhanced when its surface is partially covered by Ni (hydr)oxides or by associating it with Cu. In this work, the influence of the NaOH concentration on the hydrogen electrode kinetics on various Ni electrodes is investigated. On metallic Ni, the electrocatalytic activity (measured as an exchange current density normalized to the surface area of Ni) is almost constant between pH 12 and 14, whereas it decreases by a factor of two on partially oxidized Ni and on the NiCu/C electrode. Analyzing the current potential curves with the help of microkinetic modeling reveals that the Had and OHad binding energies on Ni do not depend on pH, whereas the rate constants of the Volmer and Heyrovsky reactions decrease with pH. The pH effect on the electron transfer elementary act is briefly discussed in the framework of a quantum mechanical theory.

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Phase Transitions Involving Dissociated States of Water at the Electrochemical Ni(111)/H2O Interface

Cited by 8 publications

References 37 publications

First Principles Analysis of the Electrocatalytic Oxidation of Methanol and Carbon Monoxide

First Principles Analysis of the Electrocatalytic Oxidation of Methanol and Carbon Monoxide

Hydrogen production by alkaline water electrolysis

Influence of the NaOH Concentration on the Hydrogen Electrode Reaction Kinetics of Ni and NiCu Electrodes

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