UCLA group designs graphene-nanopocket-encaged PtCo nanocatalysts for gas cells; extremely sturdy, ultra-low loading

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Researchers at UCLA, with colleagues at UC Irvine, have designed a graphene-nanopocket-encaged platinum cobalt (PtCo@Gnp) nanocatalyst for gas cells with good electrochemical accessibility and distinctive sturdiness beneath a demanding ultralow PGM loading (0.070 mgPGM cm–2) because of the non-contacting enclosure of graphene nanopockets.

The PtCo@Gnp delivers a state-of-the-art mass exercise of 1.21 A mgPGM–1, a rated energy of 13.2 W mgPGM–1 and a mass exercise retention of 73% after an accelerated sturdiness check. With the tremendously improved rated energy and sturdiness, the researchers challenge a 6.8 gPGM loading for a 90 kW PEMFC car; the loading approaches that utilized in a typical catalytic converter.

A paper on their work seems within the journal Nature Nanotechnology.

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The graphene-wrapped alloy yielded 75 occasions extra catalytic exercise 65% extra energy about 20% extra catalytic exercise on the anticipated finish of the gas cell’s life about 35% much less lack of energy after testing that simulates 6,000 to 7,000 hours of use, beating the goal of 5,000 hours for the primary time. Credit score:
Huang Group UCLA


This has by no means been completed earlier than. This discovery concerned some serendipity. We knew we have been onto one thing that may make smaller particles secure, however we didn’t anticipate it to work this effectively.

—corresponding writer Yu Huang, professor and chair of the Division of Supplies Science and Engineering on the UCLA Samueli College of Engineering, and a member of the California NanoSystems Institute at UCLA

In the present day, half of the full world provide of platinum and comparable metals is used for catalytic converters in automobiles powered by fossil fuels; someplace between 2 and eight grams of platinum are required per car. By comparability, present hydrogen gas cell know-how makes use of about 36 grams per car.

On the lowest load of platinum examined by Huang and her group, every hydrogen-powered car would want solely 6.8 grams of platinum.

The researchers broke up the platinum-cobalt alloy catalyst into particles a median of three nanometers lengthy; smaller particles imply extra floor space, and extra floor space means extra actual property the place catalytic exercise can happen. Nonetheless, tinier particles are additionally far much less sturdy, as a result of they have an inclination to tug off of a floor or crowd collectively into bigger particles.

Huang and her colleagues addressed this limitation by armoring their catalyst particles in graphene nanopockets, which saved the particles from migrating. On the similar time, the graphene allowed for a tiny hole of about 1 nanometer round every catalyst nanoparticle, which meant that key electrochemical reactions may happen.

This newest advance follows a current collaborative research led by Huang that produced a mannequin for predicting the catalytic exercise and sturdiness of a platinum-based alloy that can be utilized to information the design of catalysts— the primary of its type. (Earlier put up.) She and her group are working to translate their experimental outcomes into sensible know-how that may be taken to the market.

The research’s co-first authors are postdoctoral researcher Zipeng Zhao and doctoral pupil Zeyan Liu, each of UCLA. Different UCLA authors are doctoral college students Ao Zhang, Wang Xue and Bosi Peng; and Xiangfeng Duan, professor of chemistry and biochemistry at UCLA School and a member of the CNSI. UC Irvine college member Xiaoqing Pan and his postdoctoral researcher Xingxu Yan helped with imaging graphene nanopockets.

The analysis acquired funding from the US Workplace of Naval Analysis.

Sources

  • Zhao, Z., Liu, Z., Zhang, A. et al. (2022) “Graphene-nanopocket-encaged PtCo nanocatalysts for extremely sturdy gas cell operation beneath demanding ultralow-Pt-loading circumstances” Nat. Nanotechnol. doi: 10.1038/s41565-022-01170-9

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