Effect of the Surface Structure of Pt(100) and Pt(110) on the Oxidation of Carbon Monoxide in Alkaline Solution: an FTIR and Electrochemical Study

Rodríguez, Paramaconi; Garcı́a, Gonzalo; Herrero, Enrique; Feliu, Juan M.; Koper, Marc T. M.

doi:10.1007/s12678-011-0059-9

Cited by 19 publications

(9 citation statements)

References 48 publications

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“…As potassium specific adsorption becomes more favorable as pH is increased, the simulated voltammograms with coadsorbed K* represent the expected CVs in an alkaline electrolyte. These CVs compare very well with those experimentally measured in 0.1 M KOH. ,,, While we predict the competitive adsorption of hydrogen and hydroxide in an alkaline solution on Pt(110) at a slightly higher potential, 0.35 V RHE , than what is measured experimentally, 0.28 V RHE, we predict the location of the competitive adsorption peak on Pt(100) very well, 0.41 vs ∼0.4 V RHE measured experimentally . More importantly, we capture the shift with pH very well between CVs measured in 0.1 M HClO 4 and 0.1 M KOH; for Pt(110) we calculate a shift of 0.155 V RHE compared to ∼0.15 V RHE ; for Pt(100) our calculated shift of 0.09 is a little less than what is measured experimentally, ∼0.13 V RHE .…”

Section: Resultssupporting

confidence: 83%

pH and Alkali Cation Effects on the Pt Cyclic Voltammogram Explained Using Density Functional Theory

2015

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Platinum electrode cyclic voltammograms show features at low potentials which correspond to adsorption/desorption processes on Pt(111), Pt(100), and Pt(110) facets that have traditionally been ascribed to hydrogen adsorption. The 100 and 110 associated features exhibit a dependence on pH beyond the expected Nernstian shift. Herein we use density functional theory (DFT) to explain these shifts. We examine the specific adsorption of hydrogen, hydroxide, water, and potassium onto the low index facets of platinum, Pt(111), Pt(100), and Pt(110). In support of a growing body of evidence, we show that the low potential features which correspond to adsorption/desorption on Pt(100) and Pt(110) contain contributions from the competitive or coadsorption of hydroxide. This allows us to simulate cyclic voltammograms for Pt(100) and Pt(110), as well as Pt(111), which match experimentally measured cyclic voltammograms in a pH = 0 electrolyte. Furthermore, we find that potassium cations can specifically adsorb to all three low index facets of platinum, weakening the binding of hydroxide. As potassium-specific adsorption becomes more favorable with increasing pH, this allows us to explain the measured pH dependence of these features and to simulate cyclic voltammograms for the three low index facets of platinum which match experiment in a pH = 14 electrolyte. This has significant implications in catalysis for hydrogen oxidation/evolution, as well as for any electrocatalytic reaction which involves adsorbed hydroxide.

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Section: Resultssupporting

confidence: 83%

pH and Alkali Cation Effects on the Pt Cyclic Voltammogram Explained Using Density Functional Theory

2015

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“…Table presents a summary of all these data. Considering the structure of the surface, it was previously observed that, on (100) facets in alkaline solution (0.1 M NaOH), , bridge-bonded CO dominates on a Pt(100) basal plane.…”

Section: Resultsmentioning

confidence: 99%

Monitoring of CO Binding Sites on Stepped Pt Single Crystal Electrodes in Alkaline Solutions by in Situ FTIR Spectroscopy

et al. 2019

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The site geometry preference of CO binding on stepped Pt single crystals in alkaline solution was investigated by in situ FTIR spectroscopy. The surfaces of the Pt single crystals consisted of different width (111) terraces, interrupted by ( 110) or (100) monoatomic steps.Experiments carried out with CO adsorbed exclusively on the top of the steps revealed that only linearly bonded CO formed on the (110) steps, while two CO binding geometries (linear and bridge) were observed on the (100) steps. On one hand, for CO adsorbed only on the steps, the positions of the bands corresponding to linearly bonded CO were similar, regardless of the density of steps, suggesting the existence of an interaction between CO ads only along the line of the steps. On the other hand, for full CO coverage, the CO stretching frequencies and the geometry of bound CO were sensitive to the width of the (111) terraces and the step orientations. Consequently, the CO binding sites favored linearly bonded CO for surfaces consisting of shorter (111) terraces and (110) steps. Bridge-bonded CO was favored on surfaces consisting of shorter (111) terraces interrupted by (100) steps. In order to understand the origin of the preference of CO binding sites, the results were compared to the corresponding behavior in acid media, which revealed that in addition to the effect inherent to the Pt surface, the charge on the metal side in an aqueous environment should be taken into consideration.The analysis suggested that the CO adlayers formed at full coverage in acidic and alkaline media had different structures. On the other hand, the structure of the layer of CO adsorbed only at steps was independent of pH.

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“…From the surface science knowledge, the different behaviors of Pt(110) CVs were suspected to be due to the varied populations of (1 × 1) and (1 × 2) domains ((1 × 2) is a typical missing row reconstruction of (1 × 1) under surface science conditions) . For hydrogen cooled electrode, the CV at the H upd region shows two peaks at 0.12 and 0.25 V vs RHE, which should be related to the missing row (1 × 2) structure reconstruction since it was indeed observed by using in situ Fourier transform infrared technique and CV. − However, multiple reversible electrosorption peaks centered at 0.145, 0.20, and 0.25 V vs RHE for the CO-cooled electrode are not assigned properly due to the appearance of the additional 0.20 V peak, where the surface is initially dominated by the (1 × 1) surface domain. ,, To clarify the experiment, an atomic level knowledge of the electrode is required, which involves complex hydrogen adsorption/desorption states at different local atomic structures, such as terraces, steps, and reconstructed sites , and the sites with coadsorption of anion and cation. , …”

Section: Introductionmentioning

confidence: 84%

Structure and Activity of Potential-Dependent Pt(110) Surface Phases Revealed from Machine-Learning Atomic Simulation

Fang

Song

et al. 2021

J. Phys. Chem. C

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Electrodes can undergo significant surface structure reconstruction under electrochemical conditions, which in turn significantly affects its electrochemical performance. This complex phenomenon raises continuous interests in both science and industry for understanding the structure–activity dynamics under electrochemical conditions. Here we report the first theoretical attempt, by combining the machine-learning-based global optimization (SSW-NN method) and modified Poisson–Boltzmann continuum solvation (CM-MPB) based on first-principles calculations, to elucidate the potential-dependent structure evolution on a stepped Pt surface and its catalytic activity, in which the cyclic voltammetry (CV) curves are simulated to compare with experiment. We selected four types of structure domains on Pt(110), namely, Type-Ia: ordered Pt(110)-(1 × 1); Type-Ib: disordering of Pt(110)-(1 × 1); Type-II: ordered Pt(110)-(1 × 2) (the missing-row reconstruction); and Type-III: reconstructed Pt(110)-(1 × 4), and reveal the potential dependence of the coverage of H atom adsorbate, the total passed charge, and the CV of these Pt(110) surface domains. In particular, the surface reconstruction from Type-Ia to -Ib occurs at +0.20 V vs NHE when the average H coverage is above 0.60 ML, which produces the key five-coordinated Pt (Pt5c) sites. The Pt5c sites exhibit the superior activity for hydrogen evolution reaction (HER) and are the key species responsible for the high HER activity of Pt electrode.

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Effect of the Surface Structure of Pt(100) and Pt(110) on the Oxidation of Carbon Monoxide in Alkaline Solution: an FTIR and Electrochemical Study

Cited by 19 publications

References 48 publications

pH and Alkali Cation Effects on the Pt Cyclic Voltammogram Explained Using Density Functional Theory

pH and Alkali Cation Effects on the Pt Cyclic Voltammogram Explained Using Density Functional Theory

Monitoring of CO Binding Sites on Stepped Pt Single Crystal Electrodes in Alkaline Solutions by in Situ FTIR Spectroscopy

Structure and Activity of Potential-Dependent Pt(110) Surface Phases Revealed from Machine-Learning Atomic Simulation

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