Friday, 28 September 2018

Volkswagen and Stanford University develop modified ALD process to increase Pt/C fuel cell catalyst efficiency, improve durability

Source: Green Car Congress, 27 September 2018

Green Car Congress reported, "Volkswagen and Stanford University have developed in partnership a new catalyst production process to reduce the comparatively high cost of automotive fuel cell technology. (...) In the new process developed by Volkswagen and Stanford, platinum atoms are specifically placed on a carbon surface using a modified atomic layer deposition (ALD) technique in order to produce extremely thin particles. This can reduce the amount of platinum currently required to a fraction of the usual amount. The researchers published a paper in the journal Nature Catalysis earlier this year, describing the process. (...)"

Read more at: http://www.greencarcongress.com/2018/09/20180927-pald.html

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"Extending the limits of Pt/C catalysts with passivation-gas-incorporated atomic layer deposition"

Nature Catalysis, volume 1, pages 624–630 (2018), published: 30 July 2018

Abstract:

Controlling the morphology of noble metal nanoparticles during surface depositions is strongly influenced by precursor–substrate and precursor–deposit interactions. Depositions can be improved through a variety of means, including tailoring the surface energy of a substrate to improve precursor wettability, or by modifying the surface energy of the deposits themselves. Here, we show that carbon monoxide can be used as a passivation gas during atomic layer deposition to modify the surface energy of already deposited Pt nanoparticles to assist direct deposition onto a carbon catalyst support. The passivation process promotes two-dimensional growth leading to Pt nanoparticles with suppressed thicknesses and a more than 40% improvement in Pt surface-to-volume ratio. This approach to synthesizing nanoparticulate Pt/C catalysts achieved high Pt mass activities for the oxygen reduction reaction, along with excellent stability likely facilitated by strong catalyst–support interactions afforded by this synthetic technique.

https://www.nature.com/articles/s41929-018-0118-1