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Shah DD, Carter P, Shivdasani MN, Fong N, Duan W, Esrafilzadeh D, Poole-Warren LA, Aregueta Robles UA. Deciphering platinum dissolution in neural stimulation electrodes: Electrochemistry or biology? Biomaterials 2024; 309:122575. [PMID: 38677220 DOI: 10.1016/j.biomaterials.2024.122575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/28/2024] [Accepted: 04/13/2024] [Indexed: 04/29/2024]
Abstract
Platinum (Pt) is the metal of choice for electrodes in implantable neural prostheses like the cochlear implants, deep brain stimulating devices, and brain-computer interfacing technologies. However, it is well known since the 1970s that Pt dissolution occurs with electrical stimulation. More recent clinical and in vivo studies have shown signs of corrosion in explanted electrode arrays and the presence of Pt-containing particulates in tissue samples. The process of degradation and release of metallic ions and particles can significantly impact on device performance. Moreover, the effects of Pt dissolution products on tissue health and function are still largely unknown. This is due to the highly complex chemistry underlying the dissolution process and the difficulty in decoupling electrical and chemical effects on biological responses. Understanding the mechanisms and effects of Pt dissolution proves challenging as the dissolution process can be influenced by electrical, chemical, physical, and biological factors, all of them highly variable between experimental settings. By evaluating comprehensive findings on Pt dissolution mechanisms reported in the fuel cell field, this review presents a critical analysis of the possible mechanisms that drive Pt dissolution in neural stimulation in vitro and in vivo. Stimulation parameters, such as aggregate charge, charge density, and electrochemical potential can all impact the levels of dissolved Pt. However, chemical factors such as electrolyte types, dissolved gases, and pH can all influence dissolution, confounding the findings of in vitro studies with multiple variables. Biological factors, such as proteins, have been documented to exhibit a mitigating effect on the dissolution process. Other biological factors like cells and fibro-proliferative responses, such as fibrosis and gliosis, impact on electrode properties and are suspected to impact on Pt dissolution. However, the relationship between electrical properties of stimulating electrodes and Pt dissolution remains contentious. Host responses to Pt degradation products are also controversial due to the unknown chemistry of Pt compounds formed and the lack of understanding of Pt distribution in clinical scenarios. The cytotoxicity of Pt produced via electrical stimulation appears similar to Pt-based compounds, including hexachloroplatinates and chemotherapeutic agents like cisplatin. While the levels of Pt produced under clinical and acute stimulation regimes were typically an order of magnitude lower than toxic concentrations observed in vitro, further research is needed to accurately assess the mass balance and type of Pt produced during long-term stimulation and its impact on tissue response. Finally, approaches to mitigating the dissolution process are reviewed. A wide variety of approaches, including stimulation strategies, coating electrode materials, and surface modification techniques to avoid excess charge during stimulation and minimise tissue response, may ultimately support long-term and safe operation of neural stimulating devices.
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Affiliation(s)
- Dhyey Devashish Shah
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia
| | - Paul Carter
- Cochlear Ltd, Macquarie University, NSW, Australia
| | | | - Nicole Fong
- Cochlear Ltd, Macquarie University, NSW, Australia
| | - Wenlu Duan
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia
| | - Dorna Esrafilzadeh
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia
| | - Laura Anne Poole-Warren
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia; The Tyree Foundation Institute of Health Engineering, University of New South Wales, Sydney, Australia.
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2
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Kumeda T, Kondo K, Tanaka S, Sakata O, Hoshi N, Nakamura M. Surface Extraction Process During Initial Oxidation of Pt(111): Effect of Hydrophilic/Hydrophobic Cations in Alkaline Media. J Am Chem Soc 2024; 146:10312-10320. [PMID: 38506557 DOI: 10.1021/jacs.3c11334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
The surface oxidation states of the metal electrodes affect the activity, selectivity, and stability of the electrocatalysts. Oxide formation and reduction on such electrodes must be comprehensively understood to achieve next-generation electrocatalysts with outstanding performance and stability. Herein, the initial electrochemical oxidation of Pt(111) in alkaline media containing hydrophilic and hydrophobic cations is investigated by X-ray crystal truncation rod (CTR) scattering, infrared (IR) spectroscopy, and nanoparticle-based surface-enhanced Raman spectroscopy (SERS). Structural determination using X-ray CTR revealed surface buckling and Pt extraction at the initial stage of surface oxidation, depending on the cationic species. Vibrational spectroscopy is performed to identify the potential- and cation-dependent formation of three oxide species (IR-active OHad, Raman-active OHad/Oad(H2O), and Raman-active Oad). Hydrophilic alkali metal cations (Li+) inhibit surface roughening via irreversible oxide formation. Hydrophilic Li+ can strongly stabilize IR-active OHad, hindering the extraction of Pt surface atoms. Interestingly, bulky hydrophobic cations such as tetramethylammonium (TMA+) cation also reduce the extent of irreversible oxidation despite the absence of IR-active OHad. Hydrophobic TMA+ inhibits the formation of Raman-active OHad/Oad(H2O) associated with Pt extraction. In contrast, the moderate hydrophilicity of K+ has no protective effect against irreversible oxidation. Moderate hydrophilicity enables the coadsorption of Raman-active OHad/Oad(H2O) and Raman-active Oad. The electrostatic repulsion between Raman-active OHad/Oad(H2O) and neighboring Raman-active Oad promotes Pt extraction. These results provide insights into controlling the surface structures of electrocatalysts using cationic species during the oxide formation and reduction processes.
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Affiliation(s)
- Tomoaki Kumeda
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Kenshin Kondo
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Syunnosuke Tanaka
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Osami Sakata
- Center for Synchrotron Radiation Research, Japan Synchrotron Radiation Research Institute (JASRI), Sayo-gun, Hyogo 679-5198, Japan
| | - Nagahiro Hoshi
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Masashi Nakamura
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
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3
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Fuchs T, Briega-Martos V, Fehrs JO, Qiu C, Mirolo M, Yuan C, Cherevko S, Drnec J, Magnussen OM, Harrington DA. Driving Force of the Initial Step in Electrochemical Pt(111) Oxidation. J Phys Chem Lett 2023; 14:3589-3593. [PMID: 37018542 DOI: 10.1021/acs.jpclett.3c00520] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The first step of electrochemical surface oxidation is extraction of a metal atom from its lattice site to a location in a growing oxide. Here we show by fast simultaneous electrochemical and in situ high-energy surface X-ray diffraction measurements that the initial extraction of Pt atoms from Pt(111) is a fast, potential-driven process, whereas charge transfer for the related formation of adsorbed oxygen-containing species occurs on a much slower time scale and is evidently uncoupled from the extraction process. It is concluded that potential plays a key independent role in electrochemical surface oxidation.
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Affiliation(s)
- Timo Fuchs
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Olshausenstrasse 40, 24098 Kiel, Germany
| | - Valentín Briega-Martos
- Forschungszentrum Jülich GmbH, Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (IEK-11), Erlangen 91058, Germany
| | - Jan O Fehrs
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Olshausenstrasse 40, 24098 Kiel, Germany
| | - Canrong Qiu
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Olshausenstrasse 40, 24098 Kiel, Germany
| | - Marta Mirolo
- Experimental Division, European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Chentian Yuan
- Chemistry Department, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
| | - Serhiy Cherevko
- Forschungszentrum Jülich GmbH, Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (IEK-11), Erlangen 91058, Germany
| | - Jakub Drnec
- Experimental Division, European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Olaf M Magnussen
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Olshausenstrasse 40, 24098 Kiel, Germany
| | - David A Harrington
- Chemistry Department, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
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Puglia MK, Bowen PK. Cyclic Voltammetry Study of Noble Metals and Their Alloys for Use in Implantable Electrodes. ACS OMEGA 2022; 7:34200-34212. [PMID: 36188288 PMCID: PMC9520554 DOI: 10.1021/acsomega.2c03563] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/30/2022] [Indexed: 06/16/2023]
Abstract
Innovation in the application and miniaturization of implantable electrodes has caused a spike in new electrode material research; however, few robust studies are available that compare different metal electrodes in biologically relevant media. Herein, cyclic voltammetry has been employed to compare platinum, palladium, and gold-based electrodes' potentiometric scans and their corresponding charge storage capacities (CSCs). Ten different noble metals and alloys in these families were tested under pseudophysiological conditions in phosphate-buffered saline (pH 7.4) at 37 °C. Charge storage capacity values (mC/cm2) were calculated for the oxide reduction, hydrogen adsorption, hydrogen desorption, and oxide formation peaks. Five scan rates spanning 2 orders of magnitude (10, 50, 100, 500, and 1000 mV/s) in both sparged and aerated environments were evaluated. Materials have been ranked by their charge storage capacities, reversibility, and trends discussed. Palladium-based alloys outperformed platinum-based alloys in the sparged condition and were ranked equally as high in the aerated condition. The Paliney 1100 (Pd-Re) alloy gave the highest observed calculated CSC value of 0.64 ± 0.02 mC/cm2 in the aerated condition, demonstrating 73 ± 5% reversibility. Trends between metal electrode families elicited in this study can afford valuable insight into future engineering of high performing implantable electrode materials.
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Eckl MJ, Mattausch Y, Jung CK, Kirsch S, Schmidt L, Huebner G, Mueller JE, Kibler LA, Jacob T. The influence of platinum surface oxidation on the performance of a polymer electrolyte membrane fuel cell—probing changes of catalytically active surface sites on a polycrystalline platinum electrode for the oxygen reduction reaction. ELECTROCHEMICAL SCIENCE ADVANCES 2022. [DOI: 10.1002/elsa.202100049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
| | | | - Christoph Karsten Jung
- Electrochemical Energy Storage, Helmholtz‐Institute‐Ulm (HIU) Ulm Germany
- Karlsruhe Institute of Technology (KIT) Karlsruhe Germany
| | | | | | | | | | | | - Timo Jacob
- Institut für Elektrochemie Universität Ulm Ulm Germany
- Electrochemical Energy Storage, Helmholtz‐Institute‐Ulm (HIU) Ulm Germany
- Karlsruhe Institute of Technology (KIT) Karlsruhe Germany
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6
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Oxygen-Induced and pH-Induced Direct Current Artifacts on Invasive Platinum/Iridium Electrodes for Electrocorticography. Neurocrit Care 2021; 35:146-159. [PMID: 34622418 PMCID: PMC8496677 DOI: 10.1007/s12028-021-01358-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 09/15/2021] [Indexed: 12/30/2022]
Abstract
BACKGROUND Spreading depolarization (SD) and the initial, still reversible phase of neuronal cytotoxic edema in the cerebral gray matter are two modalities of the same process. SD may thus serve as a real-time mechanistic biomarker for impending parenchyma damage in patients during neurocritical care. Using subdural platinum/iridium (Pt/Ir) electrodes, SD is observed as a large negative direct current (DC) shift. Besides SD, there are other causes of DC shifts that are not to be confused with SD. Here, we systematically analyzed DC artifacts in ventilated patients by observing changes in the fraction of inspired oxygen. For the same change in blood oxygenation, we found that negative and positive DC shifts can simultaneously occur at adjacent Pt/Ir electrodes. METHODS Nurses and intensivists typically increase blood oxygenation by increasing the fraction of inspired oxygen at the ventilator before performing manipulations on the patient. We retrospectively identified 20 such episodes in six patients via tissue partial pressure of oxygen (ptiO2) measurements with an intracortical O2 sensor and analyzed the associated DC shifts. In vitro, we compared Pt/Ir with silver/silver chloride (Ag/AgCl) to assess DC responses to changes in pO2, pH, or 5-min square voltage pulses and investigated the effect of electrode polarization on pO2-induced DC artifacts. RESULTS Hyperoxygenation episodes started from a ptiO2 of 37 (30-40) mmHg (median and interquartile range) reaching 71 (50-97) mmHg. During a total of 20 episodes on each of six subdural Pt/Ir electrodes in six patients, we observed 95 predominantly negative responses in six patients, 25 predominantly positive responses in four patients, and no brain activity changes. Adjacent electrodes could show positive and negative responses simultaneously. In vitro, Pt/Ir in contrast with Ag/AgCl responded to changes in either pO2 or pH with large DC shifts. In response to square voltage pulses, Pt/Ir falsely showed smaller DC shifts than Ag/AgCl, with the worst performance under anoxia. In response to pO2 increase, Pt/Ir showed DC positivity when positively polarized and DC negativity when negatively polarized. CONCLUSIONS The magnitude of pO2-induced subdural DC shifts by approximately 6 mV was similar to that of SDs, but they did not show a sequential onset at adjacent recording sites, could be either predominantly negative or positive in contrast with the always negative DC shifts of SD, and were not accompanied by brain activity depression. Opposing polarities of pO2-induced DC artifacts may result from differences in baseline electrode polarization or subdural ptiO2 inhomogeneities relative to subdermal ptiO2 at the quasi-reference.
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Hydrogen Oxidation Artifact During Platinum Oxide Reduction in Cyclic Voltammetry Analysis of Low-Loaded PEMFC Electrodes. Electrocatalysis (N Y) 2020. [DOI: 10.1007/s12678-020-00627-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AbstractAn artifact appearing during the cathodic transient of cyclic voltammograms (CVs) of low-loaded platinum on carbon (Pt/C) electrodes in proton exchange membrane fuel cells (PEMFCs) was examined. The artifact appears as an oxidation peak overlapping the reduction peak associated to the reduction of platinum oxide (PtOx). By varying the nitrogen (N2) purge in the working electrode (WE), gas pressures in working and counter electrode, upper potential limits and scan rates of the CVs, the artifact magnitude and potential window could be manipulated. From the results, the artifact is assigned to crossover hydrogen (H2X) accumulating in the WE, once the electrode is passivated towards hydrogen oxidation reaction (HOR) due to PtOx coverage. During the cathodic CV transient, PtOx is reduced and HOR spontaneously occurs with the accumulated H2X, resulting in the overlap of the PtOx reduction with the oxidation peak. This feature is expected to occur predominantly in CV analysis of low-loaded electrodes made of catalyst material, whose oxide is inactive towards HOR. Further, it is only measurable while the N2 purge of the WE is switched off during the CV measurement. For higher loaded electrodes, the artifact is not observed as the electrocatalysts are not fully inactivated towards HOR due to incomplete oxide coverage, and/or the currents associated with the oxide reduction are much larger than the spontaneous HOR of accumulated H2X. However, owing to the forecasted reduction in noble metal loadings of catalyst in PEMFCs, this artifact is expected to be observed more often in the future.
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8
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Kristoffersen HH, Chan K, Vegge T, Hansen HA. Energy–entropy competition in cation–hydroxyl interactions at the liquid water–Pt(111) interface. Chem Commun (Camb) 2020; 56:427-430. [DOI: 10.1039/c9cc07769c] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
At water–Pt(111) interfaces, cation–*OH interactions are found to consist of both internal energy stabilizations and entropy costs emphasizing the complexity of such systems.
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Affiliation(s)
| | - Karen Chan
- Department of Physics
- Technical University of Denmark
- DK-2800 Kgs. Lyngby
- Denmark
| | - Tejs Vegge
- Department of Energy Conversion and Storage
- Technical University of Denmark
- 2800 Kgs. Lyngby
- Denmark
| | - Heine Anton Hansen
- Department of Energy Conversion and Storage
- Technical University of Denmark
- 2800 Kgs. Lyngby
- Denmark
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9
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Fernandez-Alvarez VM, Eikerling MH. Interface Properties of the Partially Oxidized Pt(111) Surface Using Hybrid DFT-Solvation Models. ACS APPLIED MATERIALS & INTERFACES 2019; 11:43774-43780. [PMID: 31650835 DOI: 10.1021/acsami.9b16326] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
This article reports a theoretical-computational effort to model the interface between an oxidized platinum surface and aqueous electrolyte. It strives to account for the impact of the electrode potential, formation of surface-bound oxygen species, orientational ordering of near-surface solvent molecules, and metal surface charging on the potential profile along the normal direction. The computational scheme is based on the DFT/ESM-RISM method to simulate the charged Pt(111) surface with varying number of oxygen adatoms in acidic solution. This hybrid solvation method is known to qualitatively reproduce bulk metal properties like the work function. However, the presented calculations reveal that vital interface properties such as the electrostatic potential at the outer Helmholtz plane are highly sensitive to the position of the metal surface slab relative to the DFT-RISM boundary region. Shifting the relative position of the slab also affects the free energy of the system. It follows that there is an optimal distance for the first solvent layer within the ESM-RISM framework, which could be found by optimizing the position of the frozen Pt(111) slab. As it stands, manual sampling of the position of the slab is impractical and betrays the self-consistency of the method. Based on this understanding, we propose the implementation of a free energy optimization scheme of the relative position of the slab in the DFT-RISM boundary region. This optimization scheme could considerably increase the applicability of the hybrid method.
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Affiliation(s)
- Victor M Fernandez-Alvarez
- Department of Chemistry , Simon Fraser University , 8888 University Drive , Burnaby , British Columbia V5A 1S6 , Canada
| | - Michael H Eikerling
- Department of Chemistry , Simon Fraser University , 8888 University Drive , Burnaby , British Columbia V5A 1S6 , Canada
- Forschungszentrum Jülich, Institute of Energy and Climate Research-Modeling and Simulation of Materials in Energy Technology (IEK-13) , 52425 Jülich , Germany
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10
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Shen D, Liu Y, Yang G, Yu H, Peng F. Mechanistic Insights into Cyclic Voltammograms on Pt(111): Kinetics Simulations. Chemphyschem 2019; 20:2791-2798. [PMID: 31509325 DOI: 10.1002/cphc.201900804] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 09/11/2019] [Indexed: 11/07/2022]
Abstract
A detailed understanding of the electrochemistry of platinum electrodes is of great importance for the electrochemical oxidation of fuels and electrochemical reduction of dioxygen in fuel cells. The Pt(111) facet is the most representative model mimicking Pt nanoparticles and polycrystals for fundamental studies. Herein, we propose a site-specific model accompanied with the typical elementary steps of the electrochemistry of Pt(111) in non-adsorbing electrolyte within the potential range between 0.05 and 1.15 V versus reversible hydrogen electrode. Simulations were conducted at different scanning rates based on the kinetics models. We reproduce all the anodic and cathodic peaks observed in the reported experimental curves. These results demonstrate the underlying mechanisms of the peak formation in different potential regions.
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Affiliation(s)
- Dongyan Shen
- School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou, Guangdong, China, 510006
| | - Yong Liu
- Department of Chemical Engineering, University of New Hampshire, Durham, New Hampshire, United States, 03824
| | - Guangxing Yang
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, Guangdong, China, 510640
| | - Hao Yu
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, Guangdong, China, 510640
| | - Feng Peng
- School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou, Guangdong, China, 510006
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11
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Malek A, Eikerling MH. Chemisorbed Oxygen at Pt(111): a DFT Study of Structural and Electronic Surface Properties. Electrocatalysis (N Y) 2017. [DOI: 10.1007/s12678-017-0436-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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12
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Wippermann K, Giffin J, Kuhri S, Lehnert W, Korte C. The influence of water content in a proton-conducting ionic liquid on the double layer properties of the Pt/PIL interface. Phys Chem Chem Phys 2017; 19:24706-24723. [PMID: 28861561 DOI: 10.1039/c7cp04003b] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The influence of the water content of 2-sulfoethylmethylammonium trifluoromethanesulfonate [2-Sema][TfO] on the double layer properties of the interface of platinum and the proton conducting ionic liquid (PIL) is investigated by means of impedance spectroscopy and cyclic voltammetry. By fitting the impedance spectra as complex capacitances, up to four differential double layer capacitances and corresponding time constants are obtained, depending on the potential (U = 0-1.6 V/RHE), water content (0.7-6.1 wt%) and temperature (T = 70-110 °C). Within the whole potential range investigated, a high frequency capacitance, C1, and a low frequency capacitance, C2, can be calculated. In the potential region of hydrogen underpotential deposition (HUPD), C1 can be separated into two parts, C1a and C1b. Whereas the high frequency capacitive processes can mainly be attributed to ion transport processes in the double layer, the low frequency process is ascribed to changes in the interfacial layer, including ad-/desorption and Faradaic processes. Alternative interpretations regarding the reorientation of ions, reconstruction of the metal surface and partial electron transfer between anions and Pt are considered.
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Affiliation(s)
- K Wippermann
- Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research - Fuel Cells (IEK-3), 52425 Jülich, Germany.
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13
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Asefa T, Huang X. Heteroatom-Doped Carbon Materials for Electrocatalysis. Chemistry 2017; 23:10703-10713. [PMID: 28397303 DOI: 10.1002/chem.201700439] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Indexed: 11/12/2022]
Abstract
Fuel cells, water electrolyzers, and metal-air batteries are important energy systems that have started to play some roles in our renewable energy landscapes. However, despite much research works carried out on them, they have not yet found large-scale applications, mainly due to the unavailability of sustainable catalysts that can catalyze the reactions employed in them. Currently, noble metal-based materials are the ones that are commonly used as catalysts in most commercial fuel cells, electrolyzers, and metal-air batteries. Hence, there has been considerable research efforts worldwide to find alternative noble metal-free and metal-free catalysts composed of inexpensive, earth-abundant elements for use in the catalytic reactions employed in these energy systems. In this concept paper, a brief introduction on catalysis in renewable energy systems, followed by the recent efforts to develop sustainable, heteroatom-doped carbon and non-noble metal-based electrocatalysts, the challenges to unravel their structure-catalytic activity relationships, and the authors' perspectives on these topics and materials, are discussed.
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Affiliation(s)
- Tewodros Asefa
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 610 Taylor Road, Piscataway, New Jersey, 08854, USA.,Department of Chemical and Biochemical Engineering, Rutgers, The State University of New Jersey, 98 Brett Road, Piscataway, New Jersey, 08854, USA
| | - Xiaoxi Huang
- Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, 610 Taylor Road, Piscataway, New Jersey, 08854, USA
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14
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Baroody HA, Jerkiewicz G, Eikerling MH. Modelling oxide formation and growth on platinum. J Chem Phys 2017; 146:144102. [DOI: 10.1063/1.4979121] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- Heather A. Baroody
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Gregory Jerkiewicz
- Department of Chemistry, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Michael H. Eikerling
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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15
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Ruge M, Drnec J, Rahn B, Reikowski F, Harrington DA, Carlà F, Felici R, Stettner J, Magnussen OM. Structural Reorganization of Pt(111) Electrodes by Electrochemical Oxidation and Reduction. J Am Chem Soc 2017; 139:4532-4539. [DOI: 10.1021/jacs.7b01039] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Martin Ruge
- Institut
für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Olshausenstraße 40, 24098 Kiel, Germany
| | - Jakub Drnec
- Experimental
Division, European Synchrotron Radiation Facility, 71 Avenue des
Martyrs, 38000 Grenoble, France
| | - Björn Rahn
- Institut
für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Olshausenstraße 40, 24098 Kiel, Germany
| | - Finn Reikowski
- Institut
für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Olshausenstraße 40, 24098 Kiel, Germany
| | - David A. Harrington
- Department
of Chemistry, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
| | - Francesco Carlà
- Experimental
Division, European Synchrotron Radiation Facility, 71 Avenue des
Martyrs, 38000 Grenoble, France
| | - Roberto Felici
- Experimental
Division, European Synchrotron Radiation Facility, 71 Avenue des
Martyrs, 38000 Grenoble, France
| | - Jochim Stettner
- Institut
für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Olshausenstraße 40, 24098 Kiel, Germany
| | - Olaf M. Magnussen
- Institut
für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Olshausenstraße 40, 24098 Kiel, Germany
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16
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Drnec J, Ruge M, Reikowski F, Rahn B, Carlà F, Felici R, Stettner J, Magnussen OM, Harrington DA. Initial stages of Pt(111) electrooxidation: dynamic and structural studies by surface X-ray diffraction. Electrochim Acta 2017. [DOI: 10.1016/j.electacta.2016.12.028] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Kim J, Munro A, Beauchemin D, Jerkiewicz G. Limits of Detection and Quantification of Electrochemical Quartz-Crystal Nanobalance in Platinum Electrochemistry and Electrocatalysis Research. Anal Chem 2016; 88:10599-10604. [PMID: 27690394 DOI: 10.1021/acs.analchem.6b02804] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The electrochemical quartz-crystal nanobalance has been used in electrochemistry research for over three decades. It provides an atomic/molecular level insight into the nature of interfacial electrochemical phenomena by measuring in situ mass changes on the nanogram scale. The sensitivity of this technique remains unknown because there have been no attempts to determine its limits of detection (LOD) or quantification (LOQ). We propose an experimental approach for determining the values of LOD and LOQ for Pt electrodes in aqueous H2SO4 solutions that employs cyclic voltammetry and frequency variation measurements. However, this methodology is also appropriate to other electrode materials and electrolytes. The LOD and LOQ values depend on the electrolyte concentration and decrease (i.e., the sensitivity increases) as the concentration decreases. Knowledge of the LOD and LOQ values determines the applicability of this technique in research on the oxidation and degradation of Pt catalysts employed in fuel cells.
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Affiliation(s)
- Jutae Kim
- Department of Chemistry, Queen's University , 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada
| | - Andrew Munro
- Department of Chemistry, Queen's University , 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada
| | - Diane Beauchemin
- Department of Chemistry, Queen's University , 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada
| | - Gregory Jerkiewicz
- Department of Chemistry, Queen's University , 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada
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Nouri-Khorasani A, Malek K, Malek A, Mashio T, Wilkinson DP, Eikerling MH. Molecular modeling of the proton density distribution in a water-filled slab-like nanopore bounded by Pt oxide and ionomer. Catal Today 2016. [DOI: 10.1016/j.cattod.2015.10.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Arce MD, Fernández JL. Oxygen reduction to water operating through the Direct (or Dissociative) Route: Descriptive and fitting capabilities of polarization curves. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.09.167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Jinnouchi R, Kodama K, Suzuki T, Morimoto Y. Kinetically induced irreversibility in electro-oxidation and reduction of Pt surface. J Chem Phys 2015; 142:184709. [PMID: 25978907 DOI: 10.1063/1.4920974] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A mean field kinetic model was developed for electrochemical oxidations and reductions of Pt(111) on the basis of density functional theory calculations, and the reaction mechanisms were analyzed. The model reasonably describes asymmetric shapes of cyclic voltammograms and small Tafel slopes of relevant redox reactions observed in experiments without assuming any unphysical forms of rate equations. Simulations using the model indicate that the oxidation of Pt(111) proceeds via an electrochemical oxidation from Pt to PtOH and a disproportionation reaction from PtOH to PtO and Pt, while its reduction proceeds via two electrochemical reductions from PtO to PtOH and from PtOH to Pt.
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Affiliation(s)
- Ryosuke Jinnouchi
- Toyota Central R&D Labs., Inc. 41-1 Yokomichi Nagakute, Aichi 480-1192, Japan
| | - Kensaku Kodama
- Toyota Central R&D Labs., Inc. 41-1 Yokomichi Nagakute, Aichi 480-1192, Japan
| | - Takahisa Suzuki
- Toyota Central R&D Labs., Inc. 41-1 Yokomichi Nagakute, Aichi 480-1192, Japan
| | - Yu Morimoto
- Toyota Central R&D Labs., Inc. 41-1 Yokomichi Nagakute, Aichi 480-1192, Japan
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