Methodology for the design of accelerated stress tests for non-precious metal catalysts in fuel cell cathodes

Sharabi, Ronit; Wijsboom, Yair H.; Borchtchoukova, Nino; Finkelshtain, Gennadi; Elbaz, Lior

doi:10.1016/j.jpowsour.2016.10.032

Cited by 14 publications

(7 citation statements)

References 31 publications

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“…Such performance loss can be attributed to a known partial instability of several carboxylate‐based complexes in alkaline conditions, or even to the sensitivity of some silver compounds due to reduction of Ag cations to metallic silver . Despite the initial current loss, the stabilization that was observed afterwards implies a positive potential for the AgBTC@AC as an ORR PGM‐free catalyst . Further study is required to understand the reasons for the initial loss of performance and to find ways to mitigate them.…”

Section: Resultsmentioning

confidence: 99%

Electrocatalytically Active Silver Organic Framework: Ag(I)‐Complex Incorporated in Activated Carbon

et al. 2019

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Silver is known as a viable alternative for platinum group metals for the catalysis of the oxygen reduction reaction in alkaline electrolyte. Unlike most other platinum-group metal-free catalysts, usually organo-metallic complexes, silver is commonly used in its metallic form (Ag(0)). Herein, we describe the preparation, characterization, and electrochemical activity of a unique silver-based catalyst, based on Ag(I) ions coordinated to oxygen groups in an organic ligand (benzene tricarboxylic acid -BTC) which forms a metal organic framework, similar to first-row transition metal-based catalysts in metal organic frameworks. When the silver-based catalyst is incorporated in a porous carbon support, it exhibits high electrocatalytic activity for the oxygen reduction reaction, with a distinct electrochemical behavior, different than metallic silver. In addition, the use of the ionic form of the silver, which is atomically dispersed, allows to lower its loading of the metal by at least one order of magnitude when compared to other reported silver-based oxygen reduction reaction catalysts. Results and DiscussionAg-BTC and Ag-BTC@AC were synthesized according to the procedure described in the experimental section. Two-probes bulk conductivity measurements showed that the AgBTC is practically an insulator, as many other metal-BTC, [5,8] unlike the high electronic conductivity of metallic silver. Therefore, AgBTC cannot be utilized as a stand-alone electrocatalyst/electrode in [a] S.

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Section: Resultsmentioning

confidence: 99%

Electrocatalytically Active Silver Organic Framework: Ag(I)‐Complex Incorporated in Activated Carbon

et al. 2019

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“…An interesting outcome is that the state of the art ORR catalysts of this class are obtained via pyrolysis of the above catalysts to form materials that apparently preserve the M-N 4 motif (metal chelated by 4 N atoms) . What seriously hampers their further development is that it is hard to design/control/identify structures and catalytic sites. , …”

Section: Introductionmentioning

confidence: 99%

“…Corroles are macrocyclic complexes with structural resemblance to porphyrins, which due to their unique trianionic platform offer enhanced activity and stability to metals chelated by them. ,− Recent work revealed that the ORR occurs with much lower overpotentials when it is catalyzed by metallocorroles rather than by metalloporphyrins and the performance is comparable to the state of the art catalysts for oxygen reduction introduced so far. − Recently, we showed that, by adsorbing the corroles on high-surface-area carbon (BP2000), the catalytic activity increases significantly with the highest activity under acidic conditions obtained with cobalt corroles, making it comparable to the state of the art catalysts for oxygen reduction introduced so far. − Nevertheless, there is still work to be done in order to further enhance the catalytic activity, mainly in shifting the ORR to the desired four-electron mechanism. It is well-known that monomeric Co porphyrins and corroles reduce oxygen via the two-electron mechanism, and that face-to-face orientation with the appropriate metal center distance is critical for the four-electron-reduction pathway. , …”

Section: Introductionmentioning

confidence: 99%

“…4 What seriously hampers their further development is that it is hard to design/ control/identify structures and catalytic sites. 4,5 However, the above aspects are quite trivial for molecular catalysts, which is actually why research performed with them is still flourishing. Within that class, significant progress has recently been reported for first-row transition-metal complexes of corroles (metallocorroles).…”

Section: Introductionmentioning

confidence: 99%

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Efficient Bio-Inspired Oxygen Reduction Electrocatalysis with Electropolymerized Cobalt Corroles

et al. 2018

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Fuel cells are considered as the only viable solution for long-range electromobility, but very rare and expensive platinum is currently required for catalyzing the bottleneck reaction therein: oxygen reduction. Within the search for catalysts that are not based on precious metals, cobalt corroles were uncovered to fulfill the requirements of high selectivity and low overpotential. We now report on the electropolymerization of a specifically designed catalyst, a cobalt(III) complex of tris(4-aminophenyl)corrole, upon which 3D polymeric structures were obtained. Much better catalytic activity was obtained by this approach in comparison to monomeric catalyst, manifested by significantly lower overpotentials, as well as higher selectivity to the desired 4e–/4H+ pathway. The performance in an alkaline environment makes it the most active molecular catalyst for the oxygen reduction reaction reported to date.

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“…The Raman spectra in Figure A show two characteristic peaks at 1300 and 1590 cm −1 for all samples, which are the D and G bands, respectively. The D band indicates defect sites due to the effect of edge sheet disruption, while the G band indicates the graphitic planar sp 2 bond . Each temperature of biomass RGO had a lower I D /I G ratio than the RGO from graphite, which also confirmed the formation of a less defective graphene material.…”

Section: Resultsmentioning

confidence: 84%

Noble‐free oxygen reduction reaction catalyst supported on Sengon wood ( Paraserianthes falcataria L. ) derived reduced graphene oxide for fuel cell application

et al. 2019

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Summary Reduced graphene oxide (RGO) has progressed as one of key emerging carbon for catalyst support material. As an alternative to the conventional RGO precursor, biomass Sengon wood was converted into RGO for use as a noble metal free catalyst support in oxygen reduction reaction (ORR). This work intends to reveal the applicability of Sengon wood‐derived RGO in anchoring/doping iron and nitrogen particles onto its surface and to study its ORR performance in a half‐cell environment. Thin‐sheet layer and highly defective (ID/IG) was gradually obtained at elevated pyrolysis temperature of Sengon wood graphene oxide (GO) at range 700°C to 900°C. As prepared RGO was further doped into catalyst (Fe/N/RGO) through the same pyrolysis procedure at a selected temperature after mixing the GO powder with iron chloride and different nitrogen precursors (urea, choline chloride, and polyaniline) at a fixed ratio. The ORR activity reached a current density up to 2.43 mA/cm2, which in conjunction with smooth multilayer sheet morphology and high graphitic‐N content as the active sites. Stability analysis indicated an 85% current efficiency and only 0.03 V reduction in onset potential on methanol resistant test for Fe/ChoCl/RGO catalyst. This study revealed that Sengon wood‐derived RGO successfully supported Fe‐N‐C catalyst which showed comparable oxygen reduction activity to Pt/C.

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Methodology for the design of accelerated stress tests for non-precious metal catalysts in fuel cell cathodes

Cited by 14 publications

References 31 publications

Electrocatalytically Active Silver Organic Framework: Ag(I)‐Complex Incorporated in Activated Carbon

Electrocatalytically Active Silver Organic Framework: Ag(I)‐Complex Incorporated in Activated Carbon

Efficient Bio-Inspired Oxygen Reduction Electrocatalysis with Electropolymerized Cobalt Corroles

Noble‐free oxygen reduction reaction catalyst supported on Sengon wood ( Paraserianthes falcataria L. ) derived reduced graphene oxide for fuel cell application

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