Electrochemical impedance spectroscopy study of borohydride oxidation reaction on gold—Towards a mechanism with two electrochemical steps

Parrour, Gaëlle; Chatenet, Marian; Diard, J.‐P.

doi:10.1016/j.electacta.2010.07.086

Cited by 22 publications

(7 citation statements)

References 50 publications

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“…15 μL s –1 , and it was obtained by using a syringe pump. In the DEMS measurements, the concentration of BH 4 – was 1.0 mmol L –1 in order to avoid extensive H 2 bubbles formation, originating from its homo/heterogeneous hydrolysis in the capillary tube of the flow cell. , Two platinum wires at the inlet and outlet of the thin-layer cell, connected through an external resistance (typically 3 MΩ), were used as counter electrodes. Hg/HgO/OH – , connected to the outlet of the DEMS cell via a Teflon capillary, served as a reference electrode.…”

Section: Methodsmentioning

confidence: 99%

“…However, several DBFC anode materials yield a poor overall faradaic efficiency, due to considerable H 2 production and subsequent losses. Consequent efforts aimed at developing materials in order to increase the fuel utilization or the number of exchanged electrons per BH 4 – species. − Nevertheless, even for the most studied metal electrocatalysts for DBFC anodes, such as Au/C, Ag/C and Pt/C, − up to now, there is lack of consensus and not enough knowledge about the dependence of the hydrolysis pathway and of the faradaic efficiency of the BOR versus electrode potential. The investigation of the hydrolysis pathway during the borohydride electrooxidation reaction can be achieved by monitoring H 2 by online techniques, such as differential electrochemical mass spectrometry (DEMS), as recently attempted for Au or Pt surfaces. , However, the investigation using stagnant electrolyte cell (the usual setup in DEMS) is limited for carbon-supported electrocatalysts, due to the required use of an electron-conducting substrate to support the working electrode (i.e., where the carbon-supported electrocatalyst is deposited), which is located in the interface with the high vacuum chamber of the mass spectrometer .…”

Section: Introductionmentioning

confidence: 99%

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Borohydride Electrooxidation on Carbon-Supported Noble Metal Nanoparticles: Insights into Hydrogen and Hydroxyborane Formation

et al. 2015

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Borohydride anions (BH4 –) are interesting as fuel for low-temperature alkaline fuel cells, owing to their high hydrogen content and low theoretical potential of oxidation. However, the borohydride electrooxidation mechanism and the potential dependence of the undesirable parallel hydrolysis pathway are not completely understood. In this study, by using a dual thin-layer flow-cell online coupled with a mass spectrometer and a rotating ring-disk electrode, the electrocatalytic activity and the dependence of the molecular hydrogen and hydroxiborane (BH3OH–) formation were investigated for carbon-supported Au, Ag, Pt, and Pd nanoparticles. For Au/C and Ag/C, the H2 and BH3OH– production presented a peak in the potential region of the first branch of the BOR wave and another increase in the metal oxide region. Pt/C and Pd/C showed accentuated H2 detection at the OCP, with a sharp decrease to practically zero after the BOR onset. Interestingly, and contrarily to what was observed for Au/C and Ag/C, the RRDE measurements showed BH3OH– production only at higher potentials (Pt- or Pd-oxides). These results were explained on the basis of the higher reactivity of Pt/C and Pd/C for the BOR, in which BH x -like species remain adsorbed and hydrogen is consumed via electrooxidation on their surfaces, at low potentials. On the other hand, Au/C and Ag/C, possessing lower reactivity (lower d-band center), the BH3-like species, produced in the first BOR steps, desorb from their surfaces and are detected at the ring. Concomitantly, at the BOR onset, H2 is formed, via recombination of adsorbed hydrogen atoms and can be detected by the mass spectrometer because these materials are relatively inactive for the hydrogen oxidation reaction.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Borohydride Electrooxidation on Carbon-Supported Noble Metal Nanoparticles: Insights into Hydrogen and Hydroxyborane Formation

et al. 2015

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“…A small number of previous studies have previously investigated PdAuNi electrocatalysts [67][68][69][70][71][72]. Au [12,[73][74][75][76][77] and Ni [25,[78][79][80], like Pd, have been proven to possess good catalytic activity towards BOR, which makes their incorporation in a catalyst additionally attractive. Specifically, in the case of Ni electrodes, the formation of β-NiOOH has been pointed out as essential for the oxidation of BH 4 − [26].…”

Section: Introductionmentioning

confidence: 99%

Nanoalloy Electrocatalysts for Electrochemical Devices

2022

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Section: Introductionmentioning

confidence: 99%

Carbon-Supported Trimetallic Catalysts (PdAuNi/C) for Borohydride Oxidation Reaction

et al. 2021

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The synthesis of palladium-based trimetallic catalysts via a facile and scalable synthesis procedure was shown to yield highly promising materials for borohydride-based fuel cells, which are attractive for use in compact environments. This, thereby, provides a route to more environmentally friendly energy storage and generation systems. Carbon-supported trimetallic catalysts were herein prepared by three different routes: using a NaBH4-ethylene glycol complex (PdAuNi/CSBEG), a NaBH4-2-propanol complex (PdAuNi/CSBIPA), and a three-step route (PdAuNi/C3-step). Notably, PdAuNi/CSBIPA yielded highly dispersed trimetallic alloy particles, as determined by XRD, EDX, ICP-OES, XPS, and TEM. The activity of the catalysts for borohydride oxidation reaction was assessed by cyclic voltammetry and RDE-based procedures, with results referenced to a Pd/C catalyst. A number of exchanged electrons close to eight was obtained for PdAuNi/C3-step and PdAuNi/CSBIPA (7.4 and 7.1, respectively), while the others, PdAuNi/CSBEG and Pd/CSBIPA, presented lower values, 2.8 and 1.2, respectively. A direct borohydride-peroxide fuel cell employing PdAuNi/CSBIPA catalyst in the anode attained a power density of 47.5 mW cm−2 at room temperature, while the elevation of temperature to 75 °C led to an approximately four-fold increase in power density to 175 mW cm−2. Trimetallic catalysts prepared via this synthesis route have significant potential for future development.

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Electrochemical impedance spectroscopy study of borohydride oxidation reaction on gold—Towards a mechanism with two electrochemical steps

Cited by 22 publications

References 50 publications

Borohydride Electrooxidation on Carbon-Supported Noble Metal Nanoparticles: Insights into Hydrogen and Hydroxyborane Formation

Borohydride Electrooxidation on Carbon-Supported Noble Metal Nanoparticles: Insights into Hydrogen and Hydroxyborane Formation

Nanoalloy Electrocatalysts for Electrochemical Devices

Carbon-Supported Trimetallic Catalysts (PdAuNi/C) for Borohydride Oxidation Reaction

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