Unlocking Proton Exchange Membrane Fuel Cell Performance with Porous PtCoV Alloy Catalysts
A non-contact Pt-ionomer microenvironment is strategically engineered to alleviate the sulfonate group-induced poisoning effect on Pt active sites by encapsulating Pt-based nanoalloys within porous nanofibers. This innovative architecture significantly enhanced proton exchange membrane fuel cell performance, achieving a remarkable peak power density of 29.0 kW gPt −1 and an exceptional initial mass activity of 0.69 A mgPt −1.
Abstract
Carbon-supported Pt-based catalysts in fuel cells often suffer from sulfonate poisoning, reducing Pt utilization and activity. Herein, a straightforward strategy is developed for synthesizing a porous PtCoV nanoalloy embedded within the porous structures of carbon nanofibers. Incorporation of vanadium (V) atoms into the PtCo alloy optimizes the oxygen binding energy of Pt sites, while heightening the dissolution energy barrier for both Pt and Co atoms, leading to a significantly enhanced intrinsic activity and durability of the catalyst. By encapsulating the nanoalloys within porous nanofibers, a non-contact Pt-ionomer interface is created to mitigate the poisoning effect of sulfonate groups to Pt sites, while promoting oxygen permeation and allowing proton transfer. This rational architecture liberates additional active Pt sites, while the evolved porous nanostructure of the PtCoV alloy extends its exposed surface area, thereby boosting Pt utilization within the catalytic layer and overall fuel cell performance. The optimized catalyst demonstrates an exceptional peak power density of 29.0 kW gPt −1 and an initial mass activity of 0.69 A mgPt −1, which exceeds the U.S. Department of Energy 2025 targets. This study provides a promising avenue for developing highly active and durable low-Pt electrocatalysts for fuel cell applications.
Creation of Independently Controllable and Long Lifetime Polar Skyrmion Textures in Ferroelectric‐Metallic Heterostructures
This work demonstrates that PTO/CCMO/SRO heterostructure can hold a broad family of skyrmion-like polar textures. One can write regular skyrmion bubble patterns with a high density ≈300 Gbit per inch2 by local tip field. The multiple π-twist target skyrmions and skyrmion bags show significant topology-enhanced stability, verifying a topology strategy to encode robust information in ferroelectrics.
Abstract
Topological textures like vortices, labyrinths, and skyrmions formed in ferroic materials have attracted extensive interest during the past decade for their fundamental physics, intriguing topology, and technological prospects. So far, polar skyrmions remain scarce in ferroelectrics as they require a delicate balance between various dipolar interactions. Here, it is reported that PbTiO3 thin films in a metallic contact undergo a topological phase transition and hold a broad family of skyrmion-like textures including Q = ±1 skyrmions, multiple π-twist target skyrmions, and skyrmion bags, with independent controllability, analogous to those reported in magnetic systems. Weakly-interacted skyrmion arrays with a density over 300 Gbit/inch2 are successfully written, erased, and read out by local electrical and mechanical stimuli of a scanning probe. Interestingly, in contrast to the relatively short lifetime (<20 hours) of the normal skyrmions, the multiple π-twist target skyrmions and skyrmion bags show topology-enhanced stability with a lifetime of over two weeks. Experimental and theoretical analysis implies the heterostructures carry electric Dzyaloshinskii–Moriya interaction mediated by oxygen octahedral tiltings. The results demonstrate ferroelectric-metallic heterostructures as fertile playgrounds for topological states and emergent phenomena.
Enhanced Polariton Interactions in Suspended WS2 Monolayer Microcavity
Monolayers of transition-metal dichalcogenides exhibit strong exciton resonances for light-matter interactions at RT, though substrate effects limit performance. This work presents a planar microcavity with a suspended WS2 monolayer, eliminating substrate-induced losses. The system shows enhancement of strong coupling and preserves the spin-dependent polaritonic interactions, achieving a record exciton interaction constant close to theoretical predictions. This approach reveals the intrinsic optical and spintronic properties of 2D materials, paving the way for advanced polaritonic.
Abstract
Transition-metal dichalcogenides monolayers exhibit strong exciton resonances that enable intense light-matter interactions. The sensitivity of these materials to the surrounding environment and their interactions with the substrate result in the enhancement of excitonic losses through scattering, dissociation and defects formation, hindering their full potential for the excitation of optical nonlinearities in exciton-polariton platforms. The use of suspended monolayers holds the potential to completely eliminate substrate-induced losses, offering unique advantages for the exploitation of intrinsic electronic, mechanical, and optical properties of 2D materials-based polaritonic systems, without any influence of proximity effects. In this work, we report a novel fabrication approach enabling the realization of a planar microcavity filled with a suspended tungsten disulfide (WS2) monolayer in its center. We experimentally demonstrate a 2-fold enhancement of the strong coupling at room temperature, due to the larger exciton binding energy and reduced overall losses as compared to similar systems based on dielectric-filled microcavities. As a result, spin-dependent polaritonic interactions are significantly amplified, leading to achievement of a record exciton interaction constant approaching the theoretically predicted value. This approach holds promises for pushing 2D materials-based polaritonic systems to their intrinsic limits, paving the way for the realization of novel polaritonic devices with superior performance.
Wed 07 May 16:00: Title to be confirmed
Abstract not available
- Speaker: Lee McIntyre (Boston University)
- Wednesday 07 May 2025, 16:00-17:00
- Venue: Ground Floor Lecture Theatre, Department of Psychology, Downing Site, Cambridge.
- Series: Social Psychology Seminar Series (SPSS); organiser: Yara Kyrychenko.
Wed 21 May 14:30: CO2 Hydration at the Air-Water Interface: A Surface-Mediated ‘In and Out’ Mechanism
An understanding of the CO2 + H2O hydration reaction is crucial for modeling the effects of ocean acidification, for enabling novel carbon storage solutions, and as a model process in the geosciences. While the mechanism of this reaction has been investigated extensively in the condensed phase, its mechanism at the air-water interface remains elusive, leaving uncertain the contribution that surface-adsorbed CO2 makes to the overall acidification reaction. In this study, we employ state-of-the-art machine-learned potentials to provide a molecular-level understanding of CO2 hydration at the air-water interface. We show that reaction at the interface follows a surface-mediated ‘In and Out’ mechanism: CO2 diffuses into the aqueous surface layer, reacts to form carbonic acid, and is subsequently expelled from solution. We show that this surface layer provides a bulk-like solvation environment, engendering similar modes of reactivity and near-identical free energy profiles for the bulk and interfacial processes. Our study unveils a new, unconventional reaction mechanism that underscores the dynamic nature of the molecular reaction site at the air-water interface. The similarity between bulk and interfacial profiles shows that CO2 hydration is equally as feasible under these two solvation environments and that acidification rates are likely enhanced by this additional surface contribution.
- Speaker: Samuel Brookes, University of Cambridge
- Wednesday 21 May 2025, 14:30-15:00
- Venue: Unilever Lecture Theatre, Yusuf Hamied Department of Chemistry.
- Series: Theory - Chemistry Research Interest Group; organiser: Lisa Masters.
Opportunities and Challenges for Emerging Inorganic Chalcogenide-Silicon Tandem Solar Cells
DOI: 10.1039/D4EE04526B, Review Article Open Access   This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.Vijay C Karade, Mingrui He, Abasi Abudulimu, Zhaoning Song, Yeonwoo Park, Donghoon Song, Yanfa Yan, Jin Hyeok Kim, Randy Ellingson, Jae Ho Yun, Xiaojing Hao, Seung Wook Shin, Mahesh P. Suryawanshi
This review highlights the promise of emerging inorganic chalcogenide-silicon (Si) tandem solar cells (TSCs) to overcome the power conversion efficiency (PCE) and long-term stability limitations of single-junction solar cells, advancing...
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An Eshelby twist to modulate thermal transport
Nature Materials, Published online: 02 May 2025; doi:10.1038/s41563-025-02186-x
By studying Eshelby twisted GeS nanowires with a single central dislocation, an anomalous dependence of thermal conductivity on nanowire diameter is observed, caused by compressive strain improving thermal transport.Spins in chains
Nature Materials, Published online: 02 May 2025; doi:10.1038/s41563-025-02243-5
One-dimensional magnetism gets the attention it deserves.Extrinsic observation and intrinsic state
Nature Materials, Published online: 02 May 2025; doi:10.1038/s41563-025-02187-w
Signatures of O2 molecules found in oxide-based battery electrodes through resonant inelastic X-ray scattering are now believed to be the extrinsic product of the intrinsic oxidized anions.Anisotropic spin transport in proximitized graphene
Nature Materials, Published online: 02 May 2025; doi:10.1038/s41563-025-02231-9
Graphene in proximity with pentagonal PdSe2 exhibits anisotropic and gate-tunable spin–orbit coupling, enabling a tenfold modulation of spin lifetime at room temperature.Extension on the Conjugated Framework of Non-fullerene Electron Acceptors toward Highly Efficient Organic Photovoltaics
DOI: 10.1039/D5EE00845J, PaperYuandong Sun, Liang Wang, Dawei Gao, Chen Chen, Zirui Gan, Jingchao Cheng, Jing Zhou, Dan Liu, Wei Li, Tao Wang
Extending the π-conjugated framework of Non-fullerene electron acceptors (NFAs) have been considered as an effective method to improve the optoelectronic properties, however, how does the conjugation extension affect the molecular...
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Wed 07 May 14:00: Reconstructing wintertime seawater pCO2 on the data-barren shelf of the western Weddell Sea based on summertime bottom water measurements
The dense waters formed on the broad shelf of the western Weddell Sea are a source of Weddell Sea Bottom Water (WSBW), which transports anthropogenic CO2 along the continental slope to the bottom of the ocean. Our updated time series shows a positive trend of carbon in WSBW . To understand the drivers for this pathway for carbon sequestration, we need to understand the processes affecting carbon concentrations in shelf waters at the time of dense water formation, which is predominantly during sea ice formation in winter. Unfortunately, wintertime marine observations are particularly scarce in the western Weddell Sea. We are therefore testing a method that reconstructs the seawater partial pressure of CO2 (pCO2) representative of wintertime conditions in this dense-water formation region, using carbonate chemistry observations made in WSBW in the summer. Results suggest that atmospheric CO2 uptake is the main driver of increasing carbon in WSBW , and thus that equilibration of surface seawater with the atmosphere is possible despite year-round sea ice cover in this region.
- Speaker: Elise Droste (University of East Anglia)
- Wednesday 07 May 2025, 14:00-15:00
- Venue: BAS Seminar Room 1.
- Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Birgit Rogalla.
Tue 06 May 14:30: Sums along binary cubic forms.
We discuss ongoing work with Joseph Leung in which we obtain estimates for sums of Fourier coefficients of GL(2) and certain GL(3) automorphic forms along the values of irreducible binary cubics.
- Speaker: Mayank Pandey (Princeton)
- Tuesday 06 May 2025, 14:30-15:30
- Venue: MR13.
- Series: Number Theory Seminar; organiser: Jef Laga.
Tue 27 May 14:00: Title to be confirmed
Abstract not available
- Speaker: Emad Heydari Beni & Lode Hoste, Nokia Bell Labs
- Tuesday 27 May 2025, 14:00-15:00
- Venue: Webinar & LT2, Computer Laboratory, William Gates Building..
- Series: Computer Laboratory Security Seminar; organiser: Anna Talas.
Tue 17 Jun 14:00: Title to be confirmed
Abstract not available
- Speaker: Michael A. Specter, Georgia Tech
- Tuesday 17 June 2025, 14:00-15:00
- Venue: Webinar & LT2, Computer Laboratory, William Gates Building..
- Series: Computer Laboratory Security Seminar; organiser: Anna Talas.
Thu 01 May 14:00: Title to be confirmed
Abstract not available
- Speaker: Michael A. Specter, Georgia Tech
- Thursday 01 May 2025, 14:00-15:00
- Venue: Webinar & LT2, Computer Laboratory, William Gates Building..
- Series: Computer Laboratory Security Seminar; organiser: Anna Talas.
Thu 12 Jun 14:00: Title to be confirmed
Abstract not available
- Speaker: Prof. Marina Filip (Oxford)
- Thursday 12 June 2025, 14:00-15:30
- Venue: Seminar Room 3, RDC.
- Series: Theory of Condensed Matter; organiser: Bo Peng.
Thu 05 Jun 14:00: Title to be confirmed
Abstract not available
- Speaker: Prof. Chris Hooley (Coventry)
- Thursday 05 June 2025, 14:00-15:30
- Venue: Seminar Room 3, RDC.
- Series: Theory of Condensed Matter; organiser: Bo Peng.
Thu 23 Oct 14:00: Title to be confirmed
Abstract not available
- Speaker: Prof. Felix Flicker (Bristol)
- Thursday 23 October 2025, 14:00-15:30
- Venue: Seminar Room 3, RDC.
- Series: Theory of Condensed Matter; organiser: Bo Peng.
Symmetrically pumped charges with high confinement stiffness for boosted performance in wave energy harvesting
DOI: 10.1039/D5EE01158B, PaperHui-jing Qiu, Wei-Zhi Song, Zichao Deng, Zhong Lin Wang, Liang Xu
Enhancing the output is the most crucial challenge for developing triboelectric nanogenerators (TENGs) as an alternative technology to exploit wave energy, which is more difficult than other application scenarios due...
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