<i>In situ</i> investigation of dissociation and migration phenomena at the Pt/electrolyte interface of an electrochemical cell

Law, Yeuk Ting; Zafeiratos, Spyridon; Neophytides, Stylianos G.; Orfanidi, Alin; Costa, Dominique; Dintzer, Thierry; Arrigo, Rosa; Knop‐Gericke, Axel; Schlögl, Robert; Savinova, Elena R.

doi:10.1039/c5sc01421b

Cited by 37 publications

(32 citation statements)

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“…Moving towards realistic operating conditions, Arrigo et al recently studied Pt nanoparticles deposited on an acidic-polymer membrane using ambient pressure X-ray photoelectron spectroscopy (APXPS) in a humidied (solid/gas interface) environment. 27 The authors found that the rst stage of Pt oxidation involves the formation of a surface Pt oxide 27,33 where atomic oxygen (O) is weakly bound to Pt (Pt-O).…”

Section: Introductionmentioning

confidence: 99%

Elucidating the alkaline oxygen evolution reaction mechanism on platinum

et al. 2017

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Understanding the interplay between surface chemistry, electronic structure, and reaction mechanism of the catalyst at the electrified solid/liquid interface will enable the design of more efficient materials systems for sustainable energy production. The substantial progress in operando characterization, particularly using synchrotron based X-ray spectroscopies, provides the unprecedented opportunity to uncover surface chemical and structural transformations under various (electro)chemical reaction environments. In this work, we study a polycrystalline platinum surface under oxygen evolution conditions in an alkaline electrolyte by means of ambient pressure X-ray photoelectron spectroscopy performed at the electrified solid/liquid interface. We elucidate previously inaccessible aspects of the surface chemistry and structure as a function of the applied potential, allowing us to propose a reaction mechanism for oxygen evolution on a platinum electrode in alkaline solutions.

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Section: Introductionmentioning

confidence: 99%

Elucidating the alkaline oxygen evolution reaction mechanism on platinum

et al. 2017

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“…Despite recent advances, nearly all in situ studies of energyrelated materials have been performed using bulk sensitive spectroscopies, such as hard X-ray XAS and XRD. The recent coupling of operational systems with surface sensitive techniques, such as X-ray photoelectron spectroscopy (XPS), provides significant opportunity for shedding new light on phenomena occurring at the solid/liquid electrified interface (38,39,40,41,42,43,44,45,46,47,48). In this work, we study, under operando conditions, the chemical and structural evolution of different conformal CoO x catalyst layers formed by plasma-enhanced atomic layer deposition (PE-ALD) on p + -Si substrates (37) as a function of the applied electrochemical potential.…”

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confidence: 99%

Understanding the Oxygen Evolution Reaction Mechanism on CoO_x using Operando Ambient-Pressure X-ray Photoelectron Spectroscopy

et al. 2017

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ABSTRACT:Photoelectrochemical water splitting is a promising approach for renewable production of hydrogen from solar energy and requires interfacing advanced water splitting catalysts with semiconductors. Understanding the mechanism of function of such electrocatalysts at the atomic scale and under realistic working conditions is a challenging, yet important, task for advancing efficient and stable function. This is particularly true for the case of oxygen evolution catalysts and, here, we study a highly active Co 3 O 4 /Co(OH) 2 biphasic electrocatalyst on Si by means of operando ambient pressure X-ray photoelectron spectroscopy performed at the solid/liquid electrified interface. Spectral simulation and multiplet fitting reveal that the catalyst undergoes chemical-structural transformations as a function of the applied anodic potential, with complete conversion of the Co(OH) 2 and partial conversion of the spinel Co 3 O 4 phases to CoO(OH) under pre-catalytic electrochemical conditions. Furthermore, we observe new spectral features in both Co 2p and O 1s core level regions to emerge under oxygen evolution reaction conditions on CoO(OH). The operando photoelectron spectra support assignment of these newly observed features to highly active Co 4+ centers under catalytic conditions. Comparison of these results to those from a pure phase spinel Co 3 O 4 catalyst supports this interpretation and reveals that the presence of Co(OH) 2 enhances catalytic activity by promoting transformations to CoO(OH). The direct investigation of electrified interfaces presented in this work can be extended to different materials under realistic catalytic conditions, thereby providing a powerful tool for mechanism discovery and an enabling capability for catalyst design. Introduction Sustainable solutions are required to mitigate the impact of increasing world energy demand on the environment and avoid depletion of natural energy sources (1). While transduction of solar energy to electricity has already made a significant impact on the renewable energy sector, the intermittent nature of sunlight imposes critical storage challenges (2,3,4,5,6). Furthermore, addressing broader energy needs, particularly in transportation, requires new technologies for the next generation of renewable fuels. Within this context, (photo)electrochemical conversion of sunlight to hydrogen -or other chemical fuels -represents an appealing approach to both solar energy conversion and high energy density storage. An essential step in such artificial photosystems is the oxygen evolution reaction (OER), in which the protons and electrons required for the fuel formation reaction are harnessed from water (2-7, 8, 9). However, OER pathways can be complex and impose significant kinetic bottlenecks. To address this challenge, increasing efforts have been devoted to developing OER catalysts possessing high activity, long-term durability, and low cost, a combination of attributes that is most commonly obtained with first row transition metal oxides (10,11,12,13,14,15...

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“…[40,41], but to the best of our knowledge have not been considered so far in the context of ORR by Pt catalysts. Our study will be divided into two parts: The main body of this work, Section 3.a, employs an implicit representation of the water solvent, allowing us to investigate in detail all the steps of the ORR.…”

Section: Resultsmentioning

confidence: 99%

Catalytic activity of Pt₃₈ in the oxygen reduction reaction from first-principles simulations

Sementa

Andreussi

Goddard

et al. 2016

Catal. Sci. Technol.

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The activity of a truncated octahedral Pt 38 clusters as a catalyst in the Oxygen Reduction Reaction (ORR) is investigated via first-principles simulations. Three catalytic steps: O 2 dissociation (O 2ads → 2 O ads ), O hydration (O ads + H 2 O ads → 2 OH ads ), and H 2 O formation (OH ads + H ads → H 2 O ads ) are considered, in which all reactant species are co-adsorbed on the Pt 38 cluster according to aLangmuir-Hinshelwood mechanism. The minimum structures and saddle points for these different steps are then calculated at the density-functional theory (DFT) level using a gradient-corrected exchange-correlation (xc-)functional and taking into account the effect of the solvent via a selfconsistent continuum solvation model. Moreover, first-principles Molecular Dynamics (AIMD) simulations in which the H 2 O solvent is explicitly described are performed to explore dynamic phenomena such as fast hydrogen transfer via meta-stable hydronium-type configurations and their possible role in ORR reaction paths. By comparing the present findings with previous results on the Pt(111) surface, it is shown that in such a nanometer-size cluster the rate-determining-step (rds) corresponds to H 2 O formation, at variance with the extended surface in which O hydration was ratedetermining, and that the overall reaction barrier is actually increased with respect to the extended system. This is in agreement with and rationalizes experimental results showing a decrease of ORR catalytic activity in the nanometer-size cluster range.

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In situ investigation of dissociation and migration phenomena at the Pt/electrolyte interface of an electrochemical cell

Abstract: Using near ambient pressure X-ray photoelectron spectroscopy we probe in situ the double layer at the Pt/liquid electrolyte interface.

Cited by 37 publications

References 46 publications

Elucidating the alkaline oxygen evolution reaction mechanism on platinum

Elucidating the alkaline oxygen evolution reaction mechanism on platinum

Understanding the Oxygen Evolution Reaction Mechanism on CoO_x using Operando Ambient-Pressure X-ray Photoelectron Spectroscopy

Catalytic activity of Pt₃₈ in the oxygen reduction reaction from first-principles simulations

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In situ investigation of dissociation and migration phenomena at the Pt/electrolyte interface of an electrochemical cell

Abstract: Using near ambient pressure X-ray photoelectron spectroscopy we probe in situ the double layer at the Pt/liquid electrolyte interface.

Cited by 37 publications

References 46 publications

Elucidating the alkaline oxygen evolution reaction mechanism on platinum

Elucidating the alkaline oxygen evolution reaction mechanism on platinum

Understanding the Oxygen Evolution Reaction Mechanism on CoOx using Operando Ambient-Pressure X-ray Photoelectron Spectroscopy

Catalytic activity of Pt38 in the oxygen reduction reaction from first-principles simulations

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Understanding the Oxygen Evolution Reaction Mechanism on CoO_x using Operando Ambient-Pressure X-ray Photoelectron Spectroscopy

Catalytic activity of Pt₃₈ in the oxygen reduction reaction from first-principles simulations