Photo-driven growth of a monolayer of platinum spherical-nanocrowns uniformly coated on a membrane toward fuel cell applications

Liu, Huiyuan; Qin, Jian‐Zhong; Rockward, Tommy; Wu, Jingtian; Li, Jia; Li, Guangwei; Mao, Qing; Lv, Yang; Wang, Xiao; Zhang, Shuomeng; Shi, Weiyu; Chen, Gang; He, Qinggang; Jiang, Ying‐Bing; Yu, Hongmei; Borup, Rodney L.; Wang, Yun; Song, Yujiang

doi:10.1039/d0ta07189g

Cited by 18 publications

(17 citation statements)

References 25 publications

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“…It can be seen that the model achieved good agreement with the experimental data using the parameters in Table 2. To achieve the agreements, it was found that the effective exchange current density ai 0,c is much smaller than the value of traditional CLs ($10 4 A m À3 for 10 mm thick CLs 25 ), which is possibly due to the small electrochemically active surface area (ECSA, $5 m 2 g Pt À1 ) as measured experimentally 27 versus that of conventional CLs ($30-50 m 2 g Pt À1 ). 18 In addition, an equivalent ionomer content 3 m of 0.0304 was adopted in the CLs, which is much lower than that of common CLs ($0.23 (ref.…”

Section: Resultsmentioning

confidence: 96%

“…1 Photo-driven method for low-Pt-loading CL fabrication. 27 The -CF2chain of the PFSA membrane is included in the gray area of the zoom-in plot. on the conservation laws of mass, momentum, species, energy, and charges in conjunction with the electrochemical kinetics in the CLs.…”

Section: The Governing Equationsmentioning

confidence: 99%

“…1. 27 The CLs with a cathodic and anodic Pt loading of 53.3 and 37.2 mg cm À2 , respectively, exhibit a power output exceeding 1.0 W cm À2 in single cell testing. Fig.…”

Section: Introductionmentioning

confidence: 95%

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A modeling study of PEM fuel cells with novel catalyst monolayers under low platinum loading

Liu

Song

et al. 2022

J. Mater. Chem. A

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Section: Resultsmentioning

confidence: 96%

Section: The Governing Equationsmentioning

confidence: 99%

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A modeling study of PEM fuel cells with novel catalyst monolayers under low platinum loading

Liu

Song

et al. 2022

J. Mater. Chem. A

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“…Each peak appears consistently with the fcc-Pt (JCPDS #04-0802), indicating the metallicity of Pt in the catalyst. , The inset is the TEM image of magnetron-sputtered Pt nanoparticles. The high-magnification TEM image clearly shows that the d -spacing between the adjacent lattice fringes is 2.3 Å, which is attributed to the planes of fcc bulk Pt ,,, (refer Supporting Information-5 for more TEM images).…”

Section: Resultsmentioning

confidence: 99%

Well-Dispersed Nafion Array Prepared by the Freeze-Drying Method to Effectively Improve the Performance of Proton Exchange Membrane Fuel Cells

Pan

Qin

Ning

et al. 2021

ACS Sustainable Chem. Eng.

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The ordered membrane electrode assembly (MEA) is currently the frontier research field of proton exchange membrane fuel cells (PEMFCs). The ordered MEA is effective in increasing the utilization of the Pt catalyst and reducing the Pt catalyst loading and cost. Due to a larger specific surface area and faster rate of proton transfer, a Nafion array was used to prepare a high-performance MEA. In order to realize the ideal performance, the critical mission is to make a well-dispersed Nafion array. However, the pillars in the Nafion array are prone to form bundles induced by surface tension of water, resulting in a severe reduction in the specific surface area. In this work, we successfully prepared a well-dispersed Nafion array by the freeze-drying method, which greatly improved the performance of the ordered MEA of a PEMFC. The percentage of isolated pillars in the Nafion array is improved from about 0.8% after natural drying to about 90% after freeze-drying. The specific surface area of the Nafion array membrane after freeze-drying increases to 4.74, which is 2.1 times that after natural drying, and is close to the theoretical value of 4.99, indicating that the well-isolated array possesses a larger specific surface area to load a catalyst. Consequently, the electrochemical surface area of the catalyst layer reaches as high as 131.5 m2 gPt –1, which is 1.6 or 2.5 times that with the Nafion array after natural drying or without the Nafion array. For the ordered MEA, a long-term stability is vital for PEMFC operation. In this work, the lifetime of the ordered MEA with the Nafion array after freeze-drying is excellent compared to the Nafion array after natural drying and without the array. Besides, the scanning electron microscopy characterization clearly shows that the Nafion array remains a well-dispersed structure even after hot-pressing and plays a pivotal role in PEMFC operation. Therefore, this research proves that the freeze-drying method can effectively solve the aggregation of the Nafion array during drying and further proves that the well-dispersed Nafion array could show much higher performance. More importantly, this work provides an ideal basic material for the preparation of the ordered MEA.

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“…In practice, Pt nanoparticles, instead of planar Pt, are usually used as electrocatalysts to improve electrochemical kinetics. At present, several approaches have been attempted to reduce the O 2 transport resistance in the ionomer–Pt interface, including removing the ionomer phase in CLs ( e.g ., 3M’s nanostructured thin film (NSTF)) and adding other species ( e.g ., ionic liquid molecules) into the ionomer. − …”

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confidence: 99%

Oxygen Transport Routes in Ionomer Film on Polyhedral Platinum Nanoparticles

2020

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Understanding the O 2 permeation phenomenon in the ionomer thin film on platinum (Pt) nanoparticles is vital to improve the electrocatalyst performance of proton exchange membrane fuel cells at a low Pt loading. In this study, the ionomer film structure, O 2 density distribution, transport fluxes, and permeation routes are investigated for carbon-supported polyhedral Pt nanoparticles (cube and tetrahedron) in the facet, edge, and corner regions. The molecular dynamic simulation takes into account the molecular interactions among the ionomer, Pt nanoparticles, carbon support, and O 2 molecules. The results show that a dense ionomer ultrathin layer with a tight arrangement of perfluorosulfonic acid is present on the Pt facets (namely region A). In the ionomer near the Pt edges and corners (namely region B), the structure is less dense due to the weaker Pt attraction, resulting in a higher O 2 density than that in region A. O 2 fluxes in the different regions show that approximately 90% of O 2 molecules reach the Pt cube and tetrahedron nanoparticles via their upper corner and edge regions. In the vicinity of Pt nanoparticles, O 2 permeation routes are inferred to penetrating region B to the Pt upper corners or edges instead of region A to the Pt facets.

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Photo-driven growth of a monolayer of platinum spherical-nanocrowns uniformly coated on a membrane toward fuel cell applications

Abstract: Membrane electrode assemblies (MEAs) serve as the core units of polymer electrolyte membrane fuel cells (PEMFCs) and are regularly fabricated by painting a slurry of commercial Pt/C onto membrane, leading...

Cited by 18 publications

References 25 publications

A modeling study of PEM fuel cells with novel catalyst monolayers under low platinum loading

A modeling study of PEM fuel cells with novel catalyst monolayers under low platinum loading

Well-Dispersed Nafion Array Prepared by the Freeze-Drying Method to Effectively Improve the Performance of Proton Exchange Membrane Fuel Cells

Oxygen Transport Routes in Ionomer Film on Polyhedral Platinum Nanoparticles

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