Borohydride electrooxidation over Pt/C, AuPt/C and Au/C catalysts: Partial reaction pathways and mixed potential formation

Jusys, Z.; Behm, R. Jürgen

doi:10.1016/j.elecom.2015.07.021

Cited by 41 publications

(21 citation statements)

References 19 publications

(17 reference statements)

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“…After this discovery, many combinations of catalysts and catalytic masses using noble metals were proposed, for example: Au, Pt and Pd bulk electrodes [5,6], palladium layers on Pt(111) [7], Pt(111) and Pt(111) modified by a pseudomorphic Pd monolayer [8], Pt/C, AuPt/C and Au/C [9,10], Pt, Ag and alloyed Pt-Ag [11], Pt nanoparticles immobilized in mesoporous silica-coated magnetic nanocapsules [12], Ru-Co-PEDOT nanocomposites [13], PdNix-B/carbon nanotube-catalysed anode [14] and platinum/polypyrrolecarbon electrocatalysts [15].…”

Section: Introductionmentioning

confidence: 99%

Structural and catalytic properties of Ni–Co spinel and its composites

et al. 2019

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Pure nickel-cobalt (Ni-Co) spinel and its two composites with active carbon and multi-walled carbon nanotubes (MWCNTs) were synthesized. X-ray diffraction confirmed the nickel cobaltites of cubic syngony and lattice constants for nanosized crystallites. Fourier transform infrared spectra confirmed an inverse spinel consisting of a tetrahedral site Co 2+ and octahedral sites Ni 2+ and Co 2+. Scanning electron microscopy images demonstrated a surface texture typical for spinels and agglomerates of composite particles with active carbon and MWCNTs. All the synthesized samples have a surface area and porosity that are sufficient for the flow of heterogeneous catalytic processes. The micropore volume of the composite with MWCNTs constituted only 4% of the total porosity, while this percentage represented 25% for the composite on the basis of active carbon. The high catalytic activity of Ni-Co spinel is proved in the model reaction of borohydride hydrolysis. To create composite spinel catalysts, active carbon showed itself to be a more efficient carrier for the catalytically active mass of spinel, as compared to MWCNTs.

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Section: Introductionmentioning

confidence: 99%

Structural and catalytic properties of Ni–Co spinel and its composites

et al. 2019

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“…This value of reaction onset potential denotes the ability of platinum to chemically hydrolyze boranes into H 2 and/or to catalyze their dissociative adsorption in BH x ,ad + H ad (H ad likely combining into H 2 below the hydrogen potential and being oxidized above this potential), as previously noted for BH 4 – . ,, Having this point in mind, one can conclude that a Pt electrode mostly performs the hydrogen electrooxidation reaction (HOR) and not the “direct” BH 3 OR; as a result, the borane electrooxidation onset is shifted toward the HOR onset (or above if the Pt electrode is poisoned by the borane cofragment). This behavior was previously reported by Molina Concha et al, , Olu et al, , and Jusys et al in the case of NaBH 4 electrooxidation. Platinum surfaces are therefore not ideal borane electrooxidation catalysts: the BH 3 OR inevitably proceeds above the hydrogen reversible potential ( E = 0 V vs RHE) because of intense spontaneous hydrolysis into H 2 or dissociative adsorption followed by the fast recombination of H ads into H 2 at Pt surfaces when the electrode potential is inferior to E = 0 V vs RHE.…”

Section: Resultsmentioning

confidence: 99%

Ubiquitous Borane Fuel Electrooxidation on Pd/C and Pt/C Electrocatalysts: Toward Promising Direct Hydrazine–Borane Fuel Cells

et al. 2018

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Carbon-supported platinum and palladium nanoparticles were studied toward the oxidation of several boranes (namely ammonia−borane (AB), dimethylamine−borane (DMAB), hydrazine−borane (HB), and hydrazine−bis-borane (HBB)); only palladium is capable to oxidize directly and efficiently these fuels, as platinum first decomposes the boranes and then valorizes the evolved H 2 and adsorbed H ad . Changing the nature of the borane fuel enables modulation of the borane oxidation performances at palladium electrodes; the best compromise is reached with HB (HBB suffers safety issues, and AB and DMAB are poisoned by the "counter-fragment" and/or its electroinactivity for any electrooxidation reaction). As a result, with a Pd/C electrode, HB oxidation is possible at low potential (close to the theoretical value), which holds promise for direct alkaline fuel cell applications. The temperature, HB concentration, and palladium nanoparticle loading on the electrode have remarkable effects, which shows that the "direct" electrooxidation of the borane fuel (BH 3 OR) or of its adsorbates may compete with its spontaneous catalytic decomposition/hydrolysis into H 2 followed by electrooxidation of H 2 (HOR). The study also highlights that the reactant time of residence influences the pathway and completion of the reactions. These results demonstrate that, using suitable electrocatalysts, well-structured electrodes, and adequate borane fuel, the BH 3 OR thermodynamic onset potential value and the theoretical number of electrons per fuel moiety (n e − = 10 in the case of HB, 6 for the borane fragment and 4 for the hydrazine one) can nearly be reached, at reasonably low anode potential, which paves the way toward optimization of direct HB fuel cell systems.

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“…[52] it is stated that the BOR on Au proceeds through the electrooxidation of BH 3ads species that originates from a partial dissociation of BH 4 ions, during which the self-dehydrogenation of BH 4 generates H 2 . The origin of H 2 production coming essentially from the dehydrogenation of BH 3ads was monitored and confirmed by differential electrochemical mass spectrometry (DEMS) [53]. Following peak A, a wide-extended oxidation wave from ca.…”

Section: Materials Characterizationmentioning

confidence: 89%

Investigation of stability of gold nanoparticles modified zinc–cobalt coating in an alkaline sodium borohydride solution

Zabielaitė¹,

Šimkūnaitė²,

Balčiūnaitė³

et al. 2020

chemija

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The electrochemical stability and durability of ZnCo alloy thin layers deposited on the titanium surface (denoted as ZnCo/Ti) and those modified by small amounts of Au nanoparticles (denoted as AuZnCo/Ti) prepared via the electrochemical metal deposition technique and a simple galvanic displacement have been investigated in alkaline sodium borohydride (NaBH4) solutions. The physical properties of the fabricated AuZnCo/Ti catalysts have been examined using field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX) and inductively coupled plasma optical emission spectroscopy (ICP-OES). The electrocatalytic activity of the ZnCo/Ti and AuZnCo/Ti catalysts toward the oxidation of NaBH4 has been evaluated in an alkaline medium using cyclic voltammetry (CV) and chronoamperometry (CA), whereas the catalytic efficiency of the catalysts for the hydrolysis reaction of NaBH4 has been also examined by measuring the amount of generated hydrogen via the classic water-displacement method. It has been determined that the modification of the ZnCo alloy coating by Au nanoparticles apparently improves not only the morphology and structure of the catalyst, but also the activity and stability of the one for the oxidation of NaBH4 in an alkaline medium as compared to those of ZnCo/Ti and bare Au. The AuZnCo/Ti catalysts that have Au loadings of 63 and 306 µg cm–2 give ca. 12 and 11, respectively, times higher NaBH4 oxidation current densities as compared to those of the bare Au catalyst. Moreover, the AuZnCo/Ti catalysts catalyze the hydrolysis reaction of NaBH4 in alkaline solutions.

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Borohydride electrooxidation over Pt/C, AuPt/C and Au/C catalysts: Partial reaction pathways and mixed potential formation

Cited by 41 publications

References 19 publications

Structural and catalytic properties of Ni–Co spinel and its composites

Structural and catalytic properties of Ni–Co spinel and its composites

Ubiquitous Borane Fuel Electrooxidation on Pd/C and Pt/C Electrocatalysts: Toward Promising Direct Hydrazine–Borane Fuel Cells

Investigation of stability of gold nanoparticles modified zinc–cobalt coating in an alkaline sodium borohydride solution

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