Optimization of platinum/iridium ratio in thin sputtered films for PEMFC cathodes

Radev, Ivan; Topalov, G.; Lefterova, E.; Ganske, G.; Schnakenberg, Uwe; Tsotridis, Georgios; Slavcheva, E.

doi:10.1016/j.ijhydene.2012.02.015

Cited by 39 publications

(20 citation statements)

References 30 publications

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“…Amongst other techniques, magnetron sputtering has been reported as a very convenient and versatile single‐step physical method for preparation of low Pt‐loading (tens of μg cm −2 ) efficient FC electrodes . This method allows deposition of thin films on virtually any solid substrate material and ensures simple and well‐defined preparation of various types of catalysts , , .…”

Section: Introductionmentioning

confidence: 72%

Efficient Pt‐C MEA for PEMFC with Low Platinum Content Prepared by Magnetron Sputtering

et al. 2018

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The presented research is focused on improvement of platinum utilization in Pt‐C composite catalysts for proton exchange membrane fuel cell (PEMFC) applications. A series of 25 nm thick nanostructured Pt‐C thin films were deposited on carbon paper gas diffusion layer substrates (GDL; Sigracet 29 BC) by a single‐step magnetron sputtering method. Total Pt loading in the thin films varied in the range 6.7–9.7 µg cm−2 as determined by X‐ray photoelectron spectroscopy (XPS). These catalysts were examined for their activity in hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR), continuously operating for periods exceeding 24 hours. The dependence of cell output power on Pt concentration and on the working pressure in the cell was examined. Membrane electrode assembly (MEA) with both magnetron sputtered electrodes and a total (anode + cathode) Pt loading 16.7 µg cm−2 was also examined during an extended 250‐hour durability test. A stable power density 0.73 W cm−2 was achieved with cell pressure of 300 kPa. Apart from reasonably small power fluctuations no long‐term efficiency loss has been detected.

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Section: Introductionmentioning

confidence: 72%

Efficient Pt‐C MEA for PEMFC with Low Platinum Content Prepared by Magnetron Sputtering

et al. 2018

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“…IrO 2 as well as Ir dendrites were shown by Oh et al to inhibit carbon corrosion in the catalyst layer by eliminating water around the carbon support [32]. Pt-Ir alloys [33][34][35][36] or mixed monolayers of Pt-Ir on Pd nanoparticles [37] have also shown enhanced catalytic activity for oxygen reduction. The Ir was also in those studies suggested to weaken the adsorption strength of OH, which lowers the OHcoverage and facilitates the ORR [34,35,37].…”

Section: Introductionmentioning

confidence: 99%

The impact of iridium on the stability of platinum on carbon thin-film model electrodes

Wesselmark¹,

Wickman²,

Lagergren³

et al. 2013

Electrochimica Acta

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a b s t r a c tIncreasing the stability and lifetime of the electrodes is one of the most important factors in order to realise a large scale use of polymer electrolyte membrane fuel cells (PEMFC). By using well-defined thin-film model electrodes, the stability of Pt and Pt on Ir were examined as cathode catalysts in a single cell PEMFC setup. The electrodes were fabricated by evaporating thin layers of Pt and Pt on Ir onto the microporous layer of a gas diffusion layer. The amount of Pt deposited was equivalent to 3 nm (about 6.3 g cm −2 ) and the amount of Ir was varied between 1.5 nm and 20 nm (between 3.4 g cm −2 and 45.3 g cm −2 ). All samples with Ir showed an increased stability over samples with sole Pt during cyclic corrosion test between 0.6 V and 1.2 V vs. the reversible hydrogen electrode. For thin layers of Ir, the initial activity for the oxygen reduction reaction was equal to or superior to that of sole Pt but for thicker Ir films it was somewhat lower. Hydrogen underpotential deposition and CO stripping were used to estimate the electrochemical surface area during the experiments and physical characterisation using scanning electron microscopy and X-ray photoelectron spectroscopy were used to determine the structure of the samples. The results suggest that Ir can stabilise Pt in the cathode electrode.

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“…Thus, the ORR activity of Pt-Ir catalysts has been extensively investigated. [25,[43][44][45][46][47] Generally, a positive effect of Ir addition to Pt on the ORR activity has been observed. The higher ORR activity of Pt alloy electrocatalysts than that of Pt alone has been mainly ascribed to geometric factors (decrease in the PtÀPt bond length) [48] or electronic factors (increase of Pt d-electron vacancy).…”

Section: Oxygen Reduction On Pt-ir Catalystsmentioning

confidence: 99%

“…In addition, Ir has stronger affinity to OH adsorption. [43,44,46,47] The Pt-Ir catalysts prepared by Huang et al [25] consisted of a physical mixture of Pt/TiO 2 and Ir/TiO 2 , clearly in a non-alloyed form. The dependence of the Pt-Ir to Pt ORR activity ratio (A PtIr /A Pt ) on Ir content in the catalyst by different data sets is shown in Figure 2.…”

Section: Oxygen Reduction On Pt-ir Catalystsmentioning

confidence: 99%

“…Indeed, when an increase in the specific activity was observed, formation of alloyed Pt-Ir catalysts was also reported. [43,44,46,47] The Pt-Ir catalysts prepared by Huang et al [25] consisted of a physical mixture of Pt/TiO 2 and Ir/TiO 2 , clearly in a non-alloyed form. As can be seen in Figure 2, for the data of Huang et al [25] (A PtIr /A Pt ) vs. x follows the following relation, indicating the absence of interactions between Pt and Ir particles [Eq.…”

Section: Oxygen Reduction On Pt-ir Catalystsmentioning

confidence: 99%

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Iridium Application in Low‐Temperature Acidic Fuel Cells: Pt‐Free Ir‐Based Catalysts or Second/Third Promoting Metal in Pt‐Based Catalysts?

Antolini¹

2013

ChemElectroChem

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Pt and Ir have similar properties, that is, same period and block (6d) of the periodic table, same fcc crystal structure, similar mass and atomic size. The cost of iridium, however, is ca. 60 % lower than that of platinum, so it could be a good substitute for Pt as a catalyst in fuel cells, also if it has to be taken into account that a large use of iridium in fuel cells could noticeably increase its price. Moreover, iridium is stable towards dissolution in acid medium. For these reasons, Pt‐free Ir‐based catalysts and Ir‐containing Pt‐based catalysts have been tested both as anode and cathode materials in low‐temperature acid fuel cells. In this work an overview of the application of Ir and Ir‐containing catalysts as anode materials for hydrogen, methanol and ethanol oxidation, and as cathode materials for oxygen reduction in low‐temperature polymer electrolyte fuel cells fuelled with hydrogen or low molecular weight alcohols, is presented. The more suitable application of iridium in fuel cell electrodes, either as non‐Pt Ir‐based catalysts, maintaining an acceptable catalytic activity, or as co‐catalysts in Pt‐based materials, to increase fuel cell performance simultaneously to a slight decrease of the cost, is discussed.

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Optimization of platinum/iridium ratio in thin sputtered films for PEMFC cathodes

Cited by 39 publications

References 30 publications

Efficient Pt‐C MEA for PEMFC with Low Platinum Content Prepared by Magnetron Sputtering

Efficient Pt‐C MEA for PEMFC with Low Platinum Content Prepared by Magnetron Sputtering

The impact of iridium on the stability of platinum on carbon thin-film model electrodes

Iridium Application in Low‐Temperature Acidic Fuel Cells: Pt‐Free Ir‐Based Catalysts or Second/Third Promoting Metal in Pt‐Based Catalysts?

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