AI Article Synopsis
- In fuel cells that use a special kind of water-based technology, tiny platinum particles need water inside their small holes to work well.
- Researchers used advanced computer simulations to study how water collects in these tiny spaces, since they can't yet see it in real life.
- The study found that when there's low humidity, the way water forms a thin layer matters, but when it's really humid, water collects more in bigger holes, helping the platinum do its job better.
Article Abstract
In polymer electrolyte membrane fuel cells, carbon-supported platinum (Pt/C) catalyst particles require sufficient water condensation within the nanoscale pores to effectively utilize the interior Pt catalysts. Since experimental visualizations with nanoscale precision of this phenomenon are not yet possible, we utilized a Pt/C catalyst particle reconstructed from segmented nanoimaging of a catalyst powder, which served as the computational domain for lattice density functional theory (LDFT) simulation of water condensation. Paired with experimental water uptake data, LDFT successfully simulated high-resolution water condensation, capturing both thin-film and capillary water condensation phenomena. Using a simple proton movement method within the water network, we reproduced the Pt utilization data from a CO stripping experiment. Our findings highlight that at low relative humidity (RH), Pt utilization is influenced by thin water film formations, mainly dictated by the wettability properties of surfaces within primary pores and the Pt/C catalyst particle's exterior. Conversely, at high RH, Pt utilization is attributed to capillary water condensation in medium-to-large sized pores. This approach contributes a qualitative and quantitative discussion on hypotheses regarding the mechanism of Pt utilization, supporting recent studies (e.g., Girod, R.; 2023, 6, (5), 383-391).
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| http://dx.doi.org/10.1021/acsami.3c19584 | DOI Listing |
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