• The main functional characteristics of electrocatalysts are their activity in reactions occurring in the catalytic layers of low-temperature fuel cells, as well as stability (maintaining activity during the operation of the fuel cell or electrolyzer). Direct comparison of these characteristics is difficult, since their values depend not only on the composition and structure of the catalysts themselves, but also on the design and composition of the porous catalytic layer, temperature, pressure and humidity of gases, some other factors. Therefore, manufacturers often indicate the values ​​of parameters characterizing the structure of Pt/C electrocatalysts: the average size of platinum nanoparticles, their spatial and size distribution; electrochemically active surface area. PEM microphotographs of fragments of their surface give a good understanding of ​​the microstructure of catalysts too.

  • Below is a table describing the composition and structure of catalysts produced by PROMETHEUS R&D, LLC using Vulcan XC72 and Ketjen black EC300 J carbon supports.

* ESA - electrochemically active surface area of ​​the catalyst per gram of platinum. It is determined by the methods of electrochemical adsorption / desorption of hydrogen and desorption of CO.

  • The figure shows curves of voltage - current and power - current dependences for membrane-electrode assembly (MEA) of a hydrogen-air fuel cell using commercial electrocatalysts (JM20, ET40) and catalysts of the PM series. The content of platinum in the catalytic layers, their composition, method of preparation, the composition and pressure of gases and all other test conditions are identical. The higher the curves lie, the higher the activity of the catalysts in the MEA.

PEM microphotographs of PM20 electrocatalyst surface fragments.

PEM microphotographs of PM40 electrocatalyst surface fragments.

PEM microphotographs of PM40 electrocatalyst surface fragments.

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