1
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Liu C, Ding R, Yin X. Comprehensive Study on the Electrochemical Evolution, Reaction Kinetics, and Mass Transport at the Anion Exchange Ionomer-Pt Interface for Oxygen Reduction Reaction. ACS APPLIED MATERIALS & INTERFACES 2024; 16:51660-51668. [PMID: 39267578 DOI: 10.1021/acsami.4c10293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/17/2024]
Abstract
Understanding the structure evolution, kinetics, and mass transfer for the oxygen reduction reaction (ORR) at the ionomer-catalyst interface is fundamental for the development of anion exchange membrane fuel cells (AEMFCs). Herein, we investigate the structural evolution of ionomer-Pt interfaces during the activation process of polycrystalline Pt (poly-Pt) electrodes and their ORR kinetics and mass transfer characteristics at steady state. The results suggest the ionomer thickness as a critical factor in determining the Pt surface structure and the flux of the O2 diffusion, which in turn affect the subsequent kinetic and mass transfer of the ORR on ionomer-Pt electrode interfaces. Thicker ionomer film leads to a more severe evolution of electrochemical features during the activation process, likely caused by forming more less-active Pt clusters at the ionomer-Pt interface. Thus, the ORR kinetic activity at the steady state decreases with the increase in ionomer thickness. Concurrently, the thicker ionomer leads to a reduced diffusion flux of O2, culminating in a lower limiting current density for the ORR. Additionally, we calculated the diffusion coefficient and solubility of O2 within the FAA-3 alkaline ionomer film, with a comparative assessment against those in the proton exchange membrane (PEM). These findings offer valuable insights into the ionomer-Pt interface in AEMFCs and their effects on performance.
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Affiliation(s)
- Chang Liu
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, Shanxi 030001, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ruimin Ding
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, Shanxi 030001, China
| | - Xi Yin
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, Shanxi 030001, China
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2
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Sharma P, Cheng L, Aaron D, Mehrazi S, Braaten J, Craig N, Johnston C, Mench MM. Unveiling Local Aging Patterns Following Accelerated Stress Testing of High-Performance Polymer Electrolyte Fuel Cells. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2306433. [PMID: 38041503 DOI: 10.1002/smll.202306433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 11/15/2023] [Indexed: 12/03/2023]
Abstract
This study presents an in-depth analysis of heterogeneous aging patterns in membrane electrode assemblies (MEAs) subjected to diverse accelerated stress test (AST) conditions, simulating carbon corrosion (CC AST) and Pt particle size growth in fully humidified (Pt AST-Wet) and underhumidified (Pt AST-Dry) H2/N2 atmospheres. Multimodal characterization techniques are used to focus on heterogeneous aging patterns, primarily examining the variations in current distributions and Pt particle size maps. The findings reveal distinct characteristics of current distributions for all the AST cases, with substantial changes and strong current gradients in the CC AST case, indicative of severe performance degradation. Notably, despite significant differences in Pt particle size growth at the end-of-life (EOL), the Pt AST-Wet and Pt AST-Dry cases show minor changes in spatial current distributions. Moreover, a preferential growth of Pt particles under serpentine flow field bends in the Pt AST-Wet case is observed for the first time. This study provides crucial insights into the role of mass transport properties in shaping fuel cell performance, and highlights the need to consider factors beyond electrochemically-active surface area (ECSA) when assessing fuel cell durability.
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Affiliation(s)
- Preetam Sharma
- Electrochemical Energy Storage and Conversion Laboratory, Department of Mechanical, Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, TN, 37919, USA
| | - Lei Cheng
- Bosch Research and Technology Center, North America, Sunnyvale, CA, 94085, USA
| | - Douglas Aaron
- Electrochemical Energy Storage and Conversion Laboratory, Department of Mechanical, Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, TN, 37919, USA
| | - Shirin Mehrazi
- Bosch Research and Technology Center, North America, Sunnyvale, CA, 94085, USA
| | - Jonathan Braaten
- Bosch Research and Technology Center, North America, Sunnyvale, CA, 94085, USA
| | - Nathan Craig
- Bosch Research and Technology Center, North America, Sunnyvale, CA, 94085, USA
| | - Christina Johnston
- Bosch Research and Technology Center, North America, Sunnyvale, CA, 94085, USA
| | - Matthew M Mench
- Electrochemical Energy Storage and Conversion Laboratory, Department of Mechanical, Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, TN, 37919, USA
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3
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Do VH, Lee JM. Surface engineering for stable electrocatalysis. Chem Soc Rev 2024; 53:2693-2737. [PMID: 38318782 DOI: 10.1039/d3cs00292f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
In recent decades, significant progress has been achieved in rational developments of electrocatalysts through constructing novel atomistic structures and modulating catalytic surface topography, realizing substantial enhancement in electrocatalytic activities. Numerous advanced catalysts were developed for electrochemical energy conversion, exhibiting low overpotential, high intrinsic activity, and selectivity. Yet, maintaining the high catalytic performance under working conditions with high polarization and vigorous microkinetics that induce intensive degradation of surface nanostructures presents a significant challenge for commercial applications. Recently, advanced operando and computational techniques have provided comprehensive mechanistic insights into the degradation of surficial functional structures. Additionally, various innovative strategies have been devised and proven effective in sustaining electrocatalytic activity under harsh operating conditions. This review aims to discuss the most recent understanding of the degradation microkinetics of catalysts across an entire range of anodic to cathodic polarizations, encompassing processes such as oxygen evolution and reduction, hydrogen reduction, and carbon dioxide reduction. Subsequently, innovative strategies adopted to stabilize the materials' structure and activity are highlighted with an in-depth discussion of the underlying rationale. Finally, we present conclusions and perspectives regarding future research and development. By identifying the research gaps, this review aims to inspire further exploration of surface degradation mechanisms and rational design of durable electrocatalysts, ultimately contributing to the large-scale utilization of electroconversion technologies.
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Affiliation(s)
- Viet-Hung Do
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459.
- Energy Research Institute @ NTU (ERI@N), Interdisciplinary Graduate School, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141
| | - Jong-Min Lee
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459.
- Energy Research Institute @ NTU (ERI@N), Interdisciplinary Graduate School, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141
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4
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Wilder L, Wyatt K, Skangos CA, Klein WE, Parimuha MR, Katsirubas JL, Young JL, Miller EM. Membranes Matter: Preventing Ammonia Crossover during Electrochemical Ammonia Synthesis. ACS APPLIED ENERGY MATERIALS 2024; 7:536-545. [PMID: 38273968 PMCID: PMC10806602 DOI: 10.1021/acsaem.3c02461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 12/13/2023] [Accepted: 12/14/2023] [Indexed: 01/27/2024]
Abstract
The electrochemical nitrogen and nitrate reduction reactions (E-NRR and E-NO3RR) promise to provide decentralized and fossil-fuel-free ammonia synthesis, and as a result, E-NRR and E-NO3RR research has surged in recent years. Membrane NH3/NH4+ crossover during E-NRR and E-NO3RR decreases Faradaic efficiency and thus the overall yield. During catalyst evaluation, such unaccounted-for crossover results in measurement error. Herein, several commercially available membranes were screened and evaluated for use in ammonia-generating electrolyzers. NH3/NH4+ crossover of the commonly used cation-exchange membrane (CEM) Nafion 212 was measured in an H-cell architecture and found to be significant. Interestingly, some anion exchange membranes (AEMs) show negligible NH4+ crossover, addressing the problem of measurement error due to NH4+ crossover. Further investigation of select membranes in a zero-gap gas diffusion electrode (GDE)-cell determines that most membranes show significant NH3 crossover when the cell is in an open circuit. However, uptake and crossover of NH3 are mitigated when -1.6 V is applied across the GDE-cell. The results of this study present AEMs as a useful alternative to CEMs for H-cell E-NRR and E-NO3RR electrolyzer studies and present critical insight into membrane crossover in zero-gap GDE-cell E-NRR and E-NO3RR electrolyzers.
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Affiliation(s)
- Logan
M. Wilder
- Chemistry
and Nanoscience Center, National Renewable
Energy Laboratory, 15013 Denver W Pkwy, Golden, Colorado 80401, United States
| | - Keenan Wyatt
- Chemistry
and Nanoscience Center, National Renewable
Energy Laboratory, 15013 Denver W Pkwy, Golden, Colorado 80401, United States
- Materials
Science and Engineering Program, University
of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Christopher A. Skangos
- Chemistry
and Nanoscience Center, National Renewable
Energy Laboratory, 15013 Denver W Pkwy, Golden, Colorado 80401, United States
| | - W. Ellis Klein
- Chemistry
and Nanoscience Center, National Renewable
Energy Laboratory, 15013 Denver W Pkwy, Golden, Colorado 80401, United States
| | - Makenzie R. Parimuha
- Chemistry
and Nanoscience Center, National Renewable
Energy Laboratory, 15013 Denver W Pkwy, Golden, Colorado 80401, United States
| | - Jaclyn L. Katsirubas
- Chemistry
and Nanoscience Center, National Renewable
Energy Laboratory, 15013 Denver W Pkwy, Golden, Colorado 80401, United States
- Department
of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - James L. Young
- Chemistry
and Nanoscience Center, National Renewable
Energy Laboratory, 15013 Denver W Pkwy, Golden, Colorado 80401, United States
| | - Elisa M. Miller
- Chemistry
and Nanoscience Center, National Renewable
Energy Laboratory, 15013 Denver W Pkwy, Golden, Colorado 80401, United States
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5
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Yarlagadda V, Mellott N, Kumaraguru S, Ramaswamy N. Proton Transport Functionality-Enabled Carbon Support for Improved Fuel Cell Performance and Durability. ACS APPLIED MATERIALS & INTERFACES 2023; 15:55669-55678. [PMID: 37983595 DOI: 10.1021/acsami.3c11528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
A novel Monarch carbon material with proton conduction capability due to the presence of sulfone/sulfoxide/sulfonic groups on the surface was evaluated as a potential cathode catalyst support to enable an electrode design with low ionomer content in proton exchange membrane (PEM) fuel cells. X-ray photoelectron spectroscopy of the carbon support confirmed the sulfonic acid functionality, while dynamic vapor sorption measurements proved higher water uptake. Electrochemical impedance spectroscopy of the PtCo/Monarch electrodes showed higher proton conductivity than state-of-the-art PtCo/C with decreasing ionomer to carbon (I/C) content due to the presence of sulfonic acid functional groups on the carbon support surface. Fuel cell performance and durability measurements showed better high-current density performance for PtCo/Monarch with a 75% lower ionomer content in the electrode compared to that of PtCo/C. Our studies indicate that Monarch carbon could be a viable alternative support for PEM fuel cell catalyst applications.
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Affiliation(s)
- Venkata Yarlagadda
- Global Fuel Cell Business, General Motors LLC, 850 N. Glenwood Avenue, Pontiac, Michigan 48340, United States
| | - Nathan Mellott
- Global Fuel Cell Business, General Motors LLC, 850 N. Glenwood Avenue, Pontiac, Michigan 48340, United States
| | - Swami Kumaraguru
- Global Fuel Cell Business, General Motors LLC, 850 N. Glenwood Avenue, Pontiac, Michigan 48340, United States
| | - Nagappan Ramaswamy
- Global Fuel Cell Business, General Motors LLC, 850 N. Glenwood Avenue, Pontiac, Michigan 48340, United States
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6
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Shao RY, Xu XC, Zhou ZH, Zeng WJ, Song TW, Yin P, Li A, Ma CS, Tong L, Kong Y, Liang HW. Promoting ordering degree of intermetallic fuel cell catalysts by low-melting-point metal doping. Nat Commun 2023; 14:5896. [PMID: 37736762 PMCID: PMC10516855 DOI: 10.1038/s41467-023-41590-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 09/11/2023] [Indexed: 09/23/2023] Open
Abstract
Carbon supported intermetallic compound nanoparticles with high activity and stability are promising cathodic catalysts for oxygen reduction reaction in proton-exchange-membrane fuel cells. However, the synthesis of intermetallic catalysts suffers from large diffusion barrier for atom ordering, resulting in low ordering degree and limited performance. We demonstrate a low-melting-point metal doping strategy for the synthesis of highly ordered L10-type M-doped PtCo (M = Ga, Pb, Sb, Cu) intermetallic catalysts. We find that the ordering degree of the M-doped PtCo catalysts increases with the decrease of melting point of M. Theoretic studies reveal that the low-melting-point metal doping can decrease the energy barrier for atom diffusion. The prepared highly ordered Ga-doped PtCo catalyst exhibits a large mass activity of 1.07 A mgPt-1 at 0.9 V in H2-O2 fuel cells and a rated power density of 1.05 W cm-2 in H2-air fuel cells, with a Pt loading of 0.075 mgPt cm-2.
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Affiliation(s)
- Ru-Yang Shao
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, China
| | - Xiao-Chu Xu
- Department of Chemistry, University of Science and Technology of China, Hefei, China
| | - Zhen-Hua Zhou
- Department of Chemistry, University of Science and Technology of China, Hefei, China
| | - Wei-Jie Zeng
- Department of Chemistry, University of Science and Technology of China, Hefei, China
| | - Tian-Wei Song
- Department of Chemistry, University of Science and Technology of China, Hefei, China
| | - Peng Yin
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, China
| | - Ang Li
- Department of Chemistry, University of Science and Technology of China, Hefei, China
| | - Chang-Song Ma
- Department of Chemistry, University of Science and Technology of China, Hefei, China
| | - Lei Tong
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, China
- Department of Chemistry, University of Science and Technology of China, Hefei, China
| | - Yuan Kong
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, China.
- Department of Chemical Physics, University of Science and Technology of China, Hefei, China.
| | - Hai-Wei Liang
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, China.
- Department of Chemistry, University of Science and Technology of China, Hefei, China.
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7
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Zeng Y, Liang J, Li C, Qiao Z, Li B, Hwang S, Kariuki NN, Chang CW, Wang M, Lyons M, Lee S, Feng Z, Wang G, Xie J, Cullen DA, Myers DJ, Wu G. Regulating Catalytic Properties and Thermal Stability of Pt and PtCo Intermetallic Fuel-Cell Catalysts via Strong Coupling Effects between Single-Metal Site-Rich Carbon and Pt. J Am Chem Soc 2023; 145:17643-17655. [PMID: 37540107 DOI: 10.1021/jacs.3c03345] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
Developing low platinum-group-metal (PGM) catalysts for the oxygen reduction reaction (ORR) in proton-exchange membrane fuel cells (PEMFCs) for heavy-duty vehicles (HDVs) remains a great challenge due to the highly demanded power density and long-term durability. This work explores the possible synergistic effect between single Mn site-rich carbon (MnSA-NC) and Pt nanoparticles, aiming to improve intrinsic activity and stability of PGM catalysts. Density functional theory (DFT) calculations predicted a strong coupling effect between Pt and MnN4 sites in the carbon support, strengthening their interactions to immobilize Pt nanoparticles during the ORR. The adjacent MnN4 sites weaken oxygen adsorption at Pt to enhance intrinsic activity. Well-dispersed Pt (2.1 nm) and ordered L12-Pt3Co nanoparticles (3.3 nm) were retained on the MnSA-NC support after indispensable high-temperature annealing up to 800 °C, suggesting enhanced thermal stability. Both PGM catalysts were thoroughly studied in membrane electrode assemblies (MEAs), showing compelling performance and durability. The Pt@MnSA-NC catalyst achieved a mass activity (MA) of 0.63 A mgPt-1 at 0.9 ViR-free and maintained 78% of its initial performance after a 30,000-cycle accelerated stress test (AST). The L12-Pt3Co@MnSA-NC catalyst accomplished a much higher MA of 0.91 A mgPt-1 and a current density of 1.63 A cm-2 at 0.7 V under traditional light-duty vehicle (LDV) H2-air conditions (150 kPaabs and 0.10 mgPt cm-2). Furthermore, the same catalyst in an HDV MEA (250 kPaabs and 0.20 mgPt cm-2) delivered 1.75 A cm-2 at 0.7 V, only losing 18% performance after 90,000 cycles of the AST, demonstrating great potential to meet the DOE targets.
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Affiliation(s)
- Yachao Zeng
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Jiashun Liang
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Chenzhao Li
- Department of Mechanical and Energy Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
- School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Zhi Qiao
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Boyang Li
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Sooyeon Hwang
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Nancy N Kariuki
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Chun-Wai Chang
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, Oregon 97331, United States
| | - Maoyu Wang
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, Oregon 97331, United States
- X-ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Mason Lyons
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, Oregon 97331, United States
| | - Sungsik Lee
- X-ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Zhenxing Feng
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, Oregon 97331, United States
| | - Guofeng Wang
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Jian Xie
- Department of Mechanical and Energy Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| | - David A Cullen
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Deborah J Myers
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Gang Wu
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
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8
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Aliyah K, Prehal C, Diercks JS, Diklić N, Xu L, Ünsal S, Appel C, Pauw BR, Smales GJ, Guizar-Sicairos M, Herranz J, Gubler L, Büchi FN, Eller J. Quantification of PEFC Catalyst Layer Saturation via In Silico, Ex Situ, and In Situ Small-Angle X-ray Scattering. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 37229747 DOI: 10.1021/acsami.3c00420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The complex nature of liquid water saturation of polymer electrolyte fuel cell (PEFC) catalyst layers (CLs) greatly affects the device performance. To investigate this problem, we present a method to quantify the presence of liquid water in a PEFC CL using small-angle X-ray scattering (SAXS). This method leverages the differences in electron densities between the solid catalyst matrix and the liquid water filled pores of the CL under both dry and wet conditions. This approach is validated using ex situ wetting experiments, which aid the study of the transient saturation of a CL in a flow cell configuration in situ. The azimuthally integrated scattering data are fitted using 3D morphology models of the CL under dry conditions. Different wetting scenarios are realized in silico, and the corresponding SAXS data are numerically simulated by a direct 3D Fourier transformation. The simulated SAXS profiles of the different wetting scenarios are used to interpret the measured SAXS data which allows the derivation of the most probable wetting mechanism within a flow cell electrode.
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Affiliation(s)
- Kinanti Aliyah
- Electrochemistry Laboratory, Paul Scherrer Institut, Villigen PSI 5232, Switzerland
| | - Christian Prehal
- Department of Information Technology and Electrical Engineering, ETH Zürich, Zürich 8092, Switzerland
| | - Justus S Diercks
- Electrochemistry Laboratory, Paul Scherrer Institut, Villigen PSI 5232, Switzerland
| | - Nataša Diklić
- Electrochemistry Laboratory, Paul Scherrer Institut, Villigen PSI 5232, Switzerland
| | - Linfeng Xu
- Electrochemistry Laboratory, Paul Scherrer Institut, Villigen PSI 5232, Switzerland
| | - Seçil Ünsal
- Electrochemistry Laboratory, Paul Scherrer Institut, Villigen PSI 5232, Switzerland
| | - Christian Appel
- Photon Science Division, Paul Scherrer Institut, Villigen PSI 5232, Switzerland
| | - Brian R Pauw
- Federal Institute for Materials Research and Testing (BAM), Berlin 12205, Germany
| | - Glen J Smales
- Federal Institute for Materials Research and Testing (BAM), Berlin 12205, Germany
| | | | - Juan Herranz
- Electrochemistry Laboratory, Paul Scherrer Institut, Villigen PSI 5232, Switzerland
| | - Lorenz Gubler
- Electrochemistry Laboratory, Paul Scherrer Institut, Villigen PSI 5232, Switzerland
| | - Felix N Büchi
- Electrochemistry Laboratory, Paul Scherrer Institut, Villigen PSI 5232, Switzerland
| | - Jens Eller
- Electrochemistry Laboratory, Paul Scherrer Institut, Villigen PSI 5232, Switzerland
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9
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Heizmann PA, Nguyen H, von Holst M, Fischbach A, Kostelec M, Gonzalez Lopez FJ, Bele M, Pavko L, Đukić T, Šala M, Ruiz-Zepeda F, Klose C, Gatalo M, Hodnik N, Vierrath S, Breitwieser M. Alternative and facile production pathway towards obtaining high surface area PtCo/C intermetallic catalysts for improved PEM fuel cell performance. RSC Adv 2023; 13:4601-4611. [PMID: 36760270 PMCID: PMC9900476 DOI: 10.1039/d2ra07780a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 01/30/2023] [Indexed: 02/09/2023] Open
Abstract
The design of catalysts with stable and finely dispersed platinum or platinum alloy nanoparticles on the carbon support is key in controlling the performance of proton exchange membrane (PEM) fuel cells. In the present work, an intermetallic PtCo/C catalyst is synthesized via double-passivation galvanic displacement. TEM and XRD confirm a significantly narrowed particle size distribution for the catalyst particles compared to commercial benchmark catalysts (Umicore PtCo/C). Only about 10% of the mass fraction of PtCo particles show a diameter larger than 8 nm, whereas this is up to or even more than 35% for the reference systems. This directly results in a considerable increase in electrochemically active surface area (96 m2 g-1 vs. >70 m2 g-1), which confirms the more efficient usage of precious catalyst metal in the novel catalyst. Single-cell tests validate this finding by improved PEM fuel cell performance. Reducing the cathode catalyst loading from 0.4 mg cm-2 to 0.25 mg cm-2 resulted in a power density drop at an application-relevant 0.7 V of only 4% for the novel catalyst, compared to the 10% and 20% for the commercial benchmarks reference catalysts.
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Affiliation(s)
- Philipp A. Heizmann
- Electrochemical Energy Systems, IMTEK – Department of Microsystems Engineering, University of FreiburgGeorges-Koehler-Allee 10379110 FreiburgGermany,Institute and FIT – Freiburg Center for Interactive Materials and Bioinspired Technologies, University of FreiburgGeorges-Köhler-Allee 10579110 FreiburgGermany
| | - Hien Nguyen
- Electrochemical Energy Systems, IMTEK - Department of Microsystems Engineering, University of Freiburg Georges-Koehler-Allee 103 79110 Freiburg Germany .,Hahn-Schickard Georges-Koehler-Allee 103 79110 Freiburg Germany
| | - Miriam von Holst
- Electrochemical Energy Systems, IMTEK - Department of Microsystems Engineering, University of Freiburg Georges-Koehler-Allee 103 79110 Freiburg Germany .,Hahn-Schickard Georges-Koehler-Allee 103 79110 Freiburg Germany
| | - Andreas Fischbach
- Electrochemical Energy Systems, IMTEK - Department of Microsystems Engineering, University of Freiburg Georges-Koehler-Allee 103 79110 Freiburg Germany
| | - Mitja Kostelec
- Department of Materials Chemistry, National Institute of ChemistryHajdrihova ulica 191000 LjubljanaSlovenia
| | - Francisco Javier Gonzalez Lopez
- Department of Materials Chemistry, National Institute of ChemistryHajdrihova ulica 191000 LjubljanaSlovenia,ReCatalyst d.o.o.Hajdrihova ulica 19Ljubljana1000Slovenia
| | - Marjan Bele
- Department of Materials Chemistry, National Institute of ChemistryHajdrihova ulica 191000 LjubljanaSlovenia
| | - Luka Pavko
- Department of Materials Chemistry, National Institute of ChemistryHajdrihova ulica 191000 LjubljanaSlovenia
| | - Tina Đukić
- Department of Materials Chemistry, National Institute of ChemistryHajdrihova ulica 191000 LjubljanaSlovenia
| | - Martin Šala
- Department of Analytical Chemistry, National Institute of ChemistryHajdrihova ulica 191000 LjubljanaSlovenia
| | - Francisco Ruiz-Zepeda
- Department of Materials Chemistry, National Institute of ChemistryHajdrihova ulica 191000 LjubljanaSlovenia
| | - Carolin Klose
- Electrochemical Energy Systems, IMTEK - Department of Microsystems Engineering, University of Freiburg Georges-Koehler-Allee 103 79110 Freiburg Germany .,Hahn-Schickard Georges-Koehler-Allee 103 79110 Freiburg Germany
| | - Matija Gatalo
- Department of Materials Chemistry, National Institute of ChemistryHajdrihova ulica 191000 LjubljanaSlovenia,ReCatalyst d.o.o.Hajdrihova ulica 19Ljubljana1000Slovenia
| | - Nejc Hodnik
- Department of Materials Chemistry, National Institute of ChemistryHajdrihova ulica 191000 LjubljanaSlovenia
| | - Severin Vierrath
- Electrochemical Energy Systems, IMTEK - Department of Microsystems Engineering, University of Freiburg Georges-Koehler-Allee 103 79110 Freiburg Germany .,Institute and FIT - Freiburg Center for Interactive Materials and Bioinspired Technologies, University of Freiburg Georges-Köhler-Allee 105 79110 Freiburg Germany.,Hahn-Schickard Georges-Koehler-Allee 103 79110 Freiburg Germany
| | - Matthias Breitwieser
- Electrochemical Energy Systems, IMTEK - Department of Microsystems Engineering, University of Freiburg Georges-Koehler-Allee 103 79110 Freiburg Germany .,Hahn-Schickard Georges-Koehler-Allee 103 79110 Freiburg Germany
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10
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Liu G, Peng S, Hou F, Wang X, Fang B. Preparation and Performance Study of the Anodic Catalyst Layer via Doctor Blade Coating for PEM Water Electrolysis. MEMBRANES 2022; 13:24. [PMID: 36676831 PMCID: PMC9860758 DOI: 10.3390/membranes13010024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 12/21/2022] [Accepted: 12/22/2022] [Indexed: 06/17/2023]
Abstract
The membrane electrode assembly (MEA) is the core component of proton exchange membrane (PEM) water electrolysis cell, which provides a place for water decomposition to generate hydrogen and oxygen. The microstructure, thickness, IrO2 loading as well as the uniformity and quality of the anodic catalyst layer (ACL) have great influence on the performance of PEM water electrolysis cell. Aiming at providing an effective and low-cost fabrication method for MEA, the purpose of this work is to optimize the catalyst ink formulation and achieve the ink properties required to form an adherent and continuous layer with doctor blade coating method. The ink formulation (e.g., isopropanol/H2O of solvents and solids content) were adjusted, and the doctor blade thickness was optimized. The porous structure and the thickness of the doctor blade coating ACL were further confirmed with the in-plane and the cross-sectional SEM analyses. Finally, the effect of the ink formulation and the doctor blade thickness of the ACL on the cell performance were characterized in a PEM electrolyzer under ambient pressure at 80 °C. Overall, the optimized doctor blade coating ACL showed comparable performance to that prepared with the spraying method. It is proved that the doctor blade coating is capable of high-uniformity coating.
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Affiliation(s)
- Gaoyang Liu
- Department of Energy Storage Science and Technology, University of Science and Technology Beijing, 30 College Road, Beijing 100083, China
- Department of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, 30 College Road, Beijing 100083, China
| | - Shanlong Peng
- Department of Energy Storage Science and Technology, University of Science and Technology Beijing, 30 College Road, Beijing 100083, China
- Department of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, 30 College Road, Beijing 100083, China
| | - Faguo Hou
- Department of Energy Storage Science and Technology, University of Science and Technology Beijing, 30 College Road, Beijing 100083, China
- Department of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, 30 College Road, Beijing 100083, China
| | - Xindong Wang
- Department of Energy Storage Science and Technology, University of Science and Technology Beijing, 30 College Road, Beijing 100083, China
- Department of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, 30 College Road, Beijing 100083, China
| | - Baizeng Fang
- Department of Energy Storage Science and Technology, University of Science and Technology Beijing, 30 College Road, Beijing 100083, China
- Department of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, 30 College Road, Beijing 100083, China
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11
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Chattot R, Roiron C, Kumar K, Martin V, Campos Roldan CA, Mirolo M, Martens I, Castanheira L, Viola A, Bacabe R, Cavaliere S, Blanchard PY, Dubau L, Maillard F, Drnec J. Break-In Bad: On the Conditioning of Fuel Cell Nanoalloy Catalysts. ACS Catal 2022. [DOI: 10.1021/acscatal.2c04495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Raphaël Chattot
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier 34095 Cedex 5, France
| | - Camille Roiron
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, Grenoble INP* (*Institute of Engineering and Management Univ. Grenoble Alpes), LEPMI, Grenoble 38000, France
| | - Kavita Kumar
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, Grenoble INP* (*Institute of Engineering and Management Univ. Grenoble Alpes), LEPMI, Grenoble 38000, France
| | - Vincent Martin
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, Grenoble INP* (*Institute of Engineering and Management Univ. Grenoble Alpes), LEPMI, Grenoble 38000, France
| | | | - Marta Mirolo
- ESRF, the European Synchrotron, 71 Avenue des Martyrs, CS40220, Grenoble 38043 Cedex 9, France
| | - Isaac Martens
- ESRF, the European Synchrotron, 71 Avenue des Martyrs, CS40220, Grenoble 38043 Cedex 9, France
| | - Luis Castanheira
- Symbio, 14 Rue Jean-Pierre Timbaud, Espace des Vouillands 2, Fontaine 38600, France
| | - Arnaud Viola
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, Grenoble INP* (*Institute of Engineering and Management Univ. Grenoble Alpes), LEPMI, Grenoble 38000, France
| | - Rémi Bacabe
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier 34095 Cedex 5, France
| | - Sara Cavaliere
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier 34095 Cedex 5, France
- Institut Universitaire de France (IUF), Paris 75231 Cedex 5, France
| | | | - Laetitia Dubau
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, Grenoble INP* (*Institute of Engineering and Management Univ. Grenoble Alpes), LEPMI, Grenoble 38000, France
| | - Frédéric Maillard
- Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, Grenoble INP* (*Institute of Engineering and Management Univ. Grenoble Alpes), LEPMI, Grenoble 38000, France
| | - Jakub Drnec
- ESRF, the European Synchrotron, 71 Avenue des Martyrs, CS40220, Grenoble 38043 Cedex 9, France
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12
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Strasser JW, Crooks RM. Ethanol Electrooxidation at 1-2 nm AuPd Nanoparticles. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:4093. [PMID: 36432379 PMCID: PMC9692959 DOI: 10.3390/nano12224093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 11/13/2022] [Accepted: 11/16/2022] [Indexed: 06/16/2023]
Abstract
We report a systematic study of the electrocatalytic properties and stability of a series of 1-2 nm Au, Pd, and AuPd alloy nanoparticles (NPs) for the ethanol oxidation reaction (EOR). Following EOR electrocatalysis, NP sizes and compositions were characterized using aberration-corrected scanning transmission electron microscopy (ac-STEM) and energy dispersive spectroscopy (EDS). Two main findings emerge from this study. First, alloyed AuPd NPs exhibit enhanced electrocatalytic EOR activity compared to either monometallic Au or Pd NPs. Specifically, NPs having a 3:1 ratio of Au:Pd exhibit an ~8-fold increase in peak current density compared to Pd NPs, with an onset potential shifted ~200 mV more to the negative compared to Au NPs. Second, the size and composition of AuPd alloy NPs do not (within experimental error) change following 1.0 or 2.0 h chronoamperometry experiments, while monometallic Au NPs increase in size from 2 to 5 nm under the same conditions. Notably, this report demonstrates the importance of post-catalytic ac-STEM/EDS characterization for fully evaluating NP activity and stability, especially for 1-2 nm NPs that may change in size or structure during electrocatalysis.
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13
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Choi J, Kim D, Chae JE, Lee S, Kim SM, Yoo SJ, Kim HJ, Choi M, Jang S. Oxygen Plasma-Mediated Microstructured Hydrocarbon Membrane for Improving Interface Adhesion and Mass Transport in Polymer Electrolyte Fuel Cells. ACS APPLIED MATERIALS & INTERFACES 2022; 14:50956-50965. [PMID: 36327306 DOI: 10.1021/acsami.2c15122] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Developing a method for fabricating high-efficient and low-cost fuel cells is imperative for commercializing polymer electrolyte membrane (PEM) fuel cells (FCs). This study introduces a mechanical and chemical modification technique using the oxygen plasma irradiation process for hydrocarbon-based (HC) PEM. The oxygen functional groups were introduced on the HC-PEM surface through the plasma process in the controlled area, and microsized structures were formed. The modified membrane was incorporated with plasma-treated electrodes, improving the adhesive force between the HC-PEM and the electrode. The decal transfer was enabled at low temperatures and pressures, and the interfacial resistance in the membrane-electrode assembly (MEA) was reduced. Furthermore, the micropillar structured electrode configuration significantly reduced the oxygen transport resistance in the MEA. Various diagnostic techniques were conducted to find out the effects of the membrane surface modification, interface adhesion, and mass transport, such as physical characterizations, mechanical stress tests, and diverse electrochemical measurements.
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Affiliation(s)
- Jiwoo Choi
- Global Frontier Center for Multiscale Energy Systems, Seoul National University, Seoul08826, Republic of Korea
- Department of Mechanical Engineering, Seoul National University, Seoul08826, Republic of Korea
| | - Dongsu Kim
- Department of Mechanical Engineering, Kookmin National University, Seoul02707, Republic of Korea
| | - Ji Eon Chae
- Department of Mobility Power Research, Korea Institute of Machinery & Materials, 156 Gajeongbuk-ro, Yuseong-gu, Daejeon34103, Korea
| | - Sanghyeok Lee
- Department of Mechanical Engineering, Kookmin National University, Seoul02707, Republic of Korea
| | - Sang Moon Kim
- Department of Mechanical Engineering, Incheon National University, Incheon22012, Republic of Korea
| | - Sung Jong Yoo
- Center for Hydrogen & Fuel Cell Research, Korea Institute of Science and Technology, Seoul02792, Korea
| | - Hyoung-Juhn Kim
- Hydrogen Energy Technology Laboratory, Korea Institute of Energy Technology (KENTECH), 200 Hyeoksin-ro, Naju, Jeonnam58330, Republic of Korea
| | - Mansoo Choi
- Global Frontier Center for Multiscale Energy Systems, Seoul National University, Seoul08826, Republic of Korea
- Department of Mechanical Engineering, Seoul National University, Seoul08826, Republic of Korea
| | - Segeun Jang
- Department of Mechanical Engineering, Kookmin National University, Seoul02707, Republic of Korea
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14
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Song TW, Xu C, Sheng ZT, Yan HK, Tong L, Liu J, Zeng WJ, Zuo LJ, Yin P, Zuo M, Chu SQ, Chen P, Liang HW. Small molecule-assisted synthesis of carbon supported platinum intermetallic fuel cell catalysts. Nat Commun 2022; 13:6521. [PMID: 36316330 PMCID: PMC9622856 DOI: 10.1038/s41467-022-34037-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 10/12/2022] [Indexed: 11/13/2022] Open
Abstract
Supported ordered intermetallic compounds exhibit superior catalytic performance over their disordered alloy counterparts in diverse reactions. But the synthesis of intermetallic compounds catalysts often requires high-temperature annealing that leads to the sintering of metals into larger crystallites. Herein, we report a small molecule-assisted impregnation approach to realize the general synthesis of a family of intermetallic catalysts, consisting of 18 binary platinum intermetallic compounds supported on carbon blacks. The molecular additives containing heteroatoms (that is, O, N, or S) can be coordinated with platinum in impregnation and thermally converted into heteroatom-doped graphene layers in high-temperature annealing, which significantly suppress alloy sintering and insure the formation of small-sized intermetallic catalysts. The prepared optimal PtCo intermetallics as cathodic oxygen-reduction catalysts exhibit a high mass activity of 1.08 A mgPt-1 at 0.9 V in H2-O2 fuel cells and a rated power density of 1.17 W cm-2 in H2-air fuel cells.
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Affiliation(s)
- Tian-Wei Song
- grid.59053.3a0000000121679639Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, 230026 China
| | - Cong Xu
- grid.59053.3a0000000121679639Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, 230026 China
| | - Zhu-Tao Sheng
- grid.440646.40000 0004 1760 6105College of Chemistry and Materials Science, Anhui Normal University, Wuhu, 241000 China
| | - Hui-Kun Yan
- grid.59053.3a0000000121679639Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, 230026 China
| | - Lei Tong
- grid.59053.3a0000000121679639Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, 230026 China
| | - Jun Liu
- grid.454811.d0000 0004 1792 7603Institute of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031 China ,Anhui Contango New Energy Technology Co., Ltd, Hefei, 230088 China
| | - Wei-Jie Zeng
- grid.59053.3a0000000121679639Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, 230026 China
| | - Lu-Jie Zuo
- grid.59053.3a0000000121679639Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, 230026 China
| | - Peng Yin
- grid.59053.3a0000000121679639Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, 230026 China
| | - Ming Zuo
- grid.59053.3a0000000121679639Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, 230026 China
| | - Sheng-Qi Chu
- grid.9227.e0000000119573309Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049 China
| | - Ping Chen
- grid.252245.60000 0001 0085 4987School of Chemistry and Chemical Engineering, Anhui University, Hefei, 230601 China
| | - Hai-Wei Liang
- grid.59053.3a0000000121679639Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei, 230026 China
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15
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Avid A, Ochoa JL, Huang Y, Liu Y, Atanassov P, Zenyuk IV. Revealing the role of ionic liquids in promoting fuel cell catalysts reactivity and durability. Nat Commun 2022; 13:6349. [PMID: 36289200 PMCID: PMC9606256 DOI: 10.1038/s41467-022-33895-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 10/07/2022] [Indexed: 11/08/2022] Open
Abstract
Ionic liquids (ILs) have shown to be promising additives to the catalyst layer to enhance oxygen reduction reaction in polymer electrolyte fuel cells. However, fundamental understanding of their role in complex catalyst layers in practically relevant membrane electrode assembly environment is needed for rational design of highly durable and active platinum-based catalysts. Here we explore three imidazolium-derived ionic liquids, selected for their high proton conductivity and oxygen solubility, and incorporate them into high surface area carbon black support. Further, we establish a correlation between the physical properties and electrochemical performance of the ionic liquid-modified catalysts by providing direct evidence of ionic liquids role in altering hydrophilic/hydrophobic interactions within the catalyst layer interface. The resulting catalyst with optimized interface design achieved a high mass activity of 347 A g-1Pt at 0.9 V under H2/O2, power density of 0.909 W cm-2 under H2/air and 1.5 bar, and had only 0.11 V potential decrease at 0.8 A cm-2 after 30 k accelerated stress test cycles. This performance stems from substantial enhancement in Pt utilization, which is buried inside the mesopores and is now accessible due to ILs addition.
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Affiliation(s)
- Arezoo Avid
- Department of Chemical and Biomolecular Engineering, University of California Irvine, 221 Engineering Service Rd., Irvine, CA, 92617, USA
- National Fuel Cell Research Center, University of California Irvine, 221 Engineering Service Rd., Irvine, CA, 92617, USA
| | - Jesus López Ochoa
- Department of Chemical and Biomolecular Engineering, University of California Irvine, 221 Engineering Service Rd., Irvine, CA, 92617, USA
- National Fuel Cell Research Center, University of California Irvine, 221 Engineering Service Rd., Irvine, CA, 92617, USA
| | - Ying Huang
- National Fuel Cell Research Center, University of California Irvine, 221 Engineering Service Rd., Irvine, CA, 92617, USA
- Department of Materials Science and Engineering, University of California Irvine, 221 Engineering Service Rd., Irvine, CA, 92617, USA
| | - Yuanchao Liu
- Department of Chemical and Biomolecular Engineering, University of California Irvine, 221 Engineering Service Rd., Irvine, CA, 92617, USA
- National Fuel Cell Research Center, University of California Irvine, 221 Engineering Service Rd., Irvine, CA, 92617, USA
| | - Plamen Atanassov
- Department of Chemical and Biomolecular Engineering, University of California Irvine, 221 Engineering Service Rd., Irvine, CA, 92617, USA
- National Fuel Cell Research Center, University of California Irvine, 221 Engineering Service Rd., Irvine, CA, 92617, USA
| | - Iryna V Zenyuk
- Department of Chemical and Biomolecular Engineering, University of California Irvine, 221 Engineering Service Rd., Irvine, CA, 92617, USA.
- National Fuel Cell Research Center, University of California Irvine, 221 Engineering Service Rd., Irvine, CA, 92617, USA.
- Department of Materials Science and Engineering, University of California Irvine, 221 Engineering Service Rd., Irvine, CA, 92617, USA.
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16
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Yu H, Zachman MJ, Reeves KS, Park JH, Kariuki NN, Hu L, Mukundan R, Neyerlin KC, Myers DJ, Cullen DA. Tracking Nanoparticle Degradation across Fuel Cell Electrodes by Automated Analytical Electron Microscopy. ACS NANO 2022; 16:12083-12094. [PMID: 35867353 PMCID: PMC9413405 DOI: 10.1021/acsnano.2c02307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Nanoparticles are an important class of materials that exhibit special properties arising from their high surface area-to-volume ratio. Scanning transmission electron microscopy (STEM) has played an important role in nanoparticle characterization, owing to its high spatial resolution, which allows direct visualization of composition and morphology with atomic precision. This typically comes at the cost of sample size, potentially limiting the accuracy and relevance of STEM results, as well as the ability to meaningfully track changes in properties that vary spatially. In this work, automated STEM data acquisition and analysis techniques are employed that enable physical and compositional properties of nanoparticles to be obtained at high resolution over length scales on the order of microns. This is demonstrated by studying the localized effects of potential cycling on electrocatalyst degradation across proton exchange membrane fuel cell cathodes. In contrast to conventional, manual STEM measurements, which produce particle size distributions representing hundreds of particles, these high-throughput automated methods capture tens of thousands of particles and enable nanoparticle size, number density, and composition to be measured as a function of position within the cathode. Comparing the properties of pristine and degraded fuel cells provides statistically robust evidence for the inhomogeneous nature of catalyst degradation across electrodes. These results demonstrate how high-throughput automated STEM techniques can be utilized to investigate local phenomena occurring in nanoparticle systems employed in practical devices.
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Affiliation(s)
- Haoran Yu
- Center
for Nanophase Materials Sciences, Oak Ridge
National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Michael J. Zachman
- Center
for Nanophase Materials Sciences, Oak Ridge
National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Kimberly S. Reeves
- Center
for Nanophase Materials Sciences, Oak Ridge
National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Jae Hyung Park
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, Lemont, Illinois 60439, United States
| | - Nancy N. Kariuki
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, Lemont, Illinois 60439, United States
| | - Leiming Hu
- Chemistry
and Nanoscience Center, National Renewable
Energy Laboratory, Golden, Colorado 80401, United States
| | - Rangachary Mukundan
- Materials
Physics and Applications Division, Los Alamos
National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Kenneth C. Neyerlin
- Chemistry
and Nanoscience Center, National Renewable
Energy Laboratory, Golden, Colorado 80401, United States
| | - Deborah J. Myers
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, Lemont, Illinois 60439, United States
| | - David A. Cullen
- Center
for Nanophase Materials Sciences, Oak Ridge
National Laboratory, Oak Ridge, Tennessee 37831, United States
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17
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Khedekar K, Satjaritanun P, Stewart S, Braaten J, Atanassov P, Tamura N, Cheng L, Johnston CM, Zenyuk IV. Effect of Commercial Gas Diffusion Layers on Catalyst Durability of Polymer Electrolyte Fuel Cells in Varied Cathode Gas Environment. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2201750. [PMID: 35871500 DOI: 10.1002/smll.202201750] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 07/04/2022] [Indexed: 06/15/2023]
Abstract
Gas diffusion layers (GDLs) play a crucial role in heat transfer and water management of cathode catalyst layers in polymer electrolyte fuel cells (PEFCs). Thermal and water gradients can accelerate electrocatalyst degradation and therefore the selection of GDLs can have a major influence on PEFC durability. Currently, the role of GDLs in electrocatalyst degradation is poorly studied. In this study, electrocatalyst accelerated stress test studies are performed on membrane electrode assemblies (MEAs) prepared using three most commonly used GDLs. The effect of GDLs on electrocatalyst degradation is evaluated in both nitrogen (non-reactive) and air (reactive) gas environments at 100% relative humidity. In situ electrochemical characterization and extensive physical characterization is performed to understand the subtle differences in electrocatalyst degradation and correlated to the use of different GDLs. Overall, no difference is observed in the electrocatalyst degradation due to GDLs based on polarization curves at the end of life. But interestingly, MEA with a cracked microporous layer (MPL) in the GDL exhibited a higher electrocatalyst loading loss, which resulted in a lower and more heterogeneous increase in the average electrocatalyst nanoparticle size.
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Affiliation(s)
- Kaustubh Khedekar
- Department of Material Science and Engineering; National Fuel Cell Research Center, University of California, Irvine, CA, 92697, USA
| | - Pongsarun Satjaritanun
- Department of Chemical and Biomolecular Engineering; National Fuel Cell Research Center, University of California, Irvine, CA, 92697, USA
| | - Sarah Stewart
- Bosch Research and Technology Center North America, Sunnyvale, CA, 94085, USA
| | - Jonathan Braaten
- Bosch Research and Technology Center North America, Sunnyvale, CA, 94085, USA
| | - Plamen Atanassov
- Department of Material Science and Engineering; National Fuel Cell Research Center, University of California, Irvine, CA, 92697, USA
- Department of Chemical and Biomolecular Engineering; National Fuel Cell Research Center, University of California, Irvine, CA, 92697, USA
| | - Nobumichi Tamura
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Lei Cheng
- Bosch Research and Technology Center North America, Sunnyvale, CA, 94085, USA
| | | | - Iryna V Zenyuk
- Department of Material Science and Engineering; National Fuel Cell Research Center, University of California, Irvine, CA, 92697, USA
- Department of Chemical and Biomolecular Engineering; National Fuel Cell Research Center, University of California, Irvine, CA, 92697, USA
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18
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Atomically dispersed Pt and Fe sites and Pt–Fe nanoparticles for durable proton exchange membrane fuel cells. Nat Catal 2022. [DOI: 10.1038/s41929-022-00796-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
AbstractProton exchange membrane fuel cells convert hydrogen and oxygen into electricity without emissions. The high cost and low durability of Pt-based electrocatalysts for the oxygen reduction reaction hinder their wide application, and the development of non-precious metal electrocatalysts is limited by their low performance. Here we design a hybrid electrocatalyst that consists of atomically dispersed Pt and Fe single atoms and Pt–Fe alloy nanoparticles. Its Pt mass activity is 3.7 times higher than that of commercial Pt/C in a fuel cell. More importantly, the fuel cell with a low Pt loading in the cathode (0.015 mgPt cm−2) shows an excellent durability, with a 97% activity retention after 100,000 cycles and no noticeable current drop at 0.6 V for over 200 hours. These results highlight the importance of the synergistic effects among active sites in hybrid electrocatalysts and provide an alternative way to design more active and durable low-Pt electrocatalysts for electrochemical devices.
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19
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Strasser JW, Hersbach TJP, Liu J, Lapp AS, Frenkel AI, Crooks RM. Electrochemical Cleaning Stability and Oxygen Reduction Reaction Activity of 1‐2 nm Dendrimer‐Encapsulated Au Nanoparticles. ChemElectroChem 2021. [DOI: 10.1002/celc.202100549] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Juliette W. Strasser
- Department of Chemistry and Texas Materials Institute The University of Texas at Austin 2506 Speedway, Stop A5300 Austin TX 78712-1224, U.S.A
| | - Thomas J. P. Hersbach
- Department of Chemistry and Texas Materials Institute The University of Texas at Austin 2506 Speedway, Stop A5300 Austin TX 78712-1224, U.S.A
| | - Jing Liu
- Department of Physics Manhattan College Riverdale NY 10471 USA
| | - Aliya S. Lapp
- Department of Chemistry and Texas Materials Institute The University of Texas at Austin 2506 Speedway, Stop A5300 Austin TX 78712-1224, U.S.A
| | - Anatoly I. Frenkel
- Department of Materials Science and Chemical Engineering Stony Brook University Stony Brook NY 11794 USA
- Division of Chemistry Brookhaven National Laboratory Upton NY 11973 USA
| | - Richard M. Crooks
- Department of Chemistry and Texas Materials Institute The University of Texas at Austin 2506 Speedway, Stop A5300 Austin TX 78712-1224, U.S.A
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20
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Enhanced self-humidification and proton conductivity in magnetically aligned NiO-Co3O4/chitosan nanocomposite membranes for high-temperature PEMFCs. Polym J 2021. [DOI: 10.1038/s41428-021-00466-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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21
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Lu BA, Shen LF, Liu J, Zhang Q, Wan LY, Morris DJ, Wang RX, Zhou ZY, Li G, Sheng T, Gu L, Zhang P, Tian N, Sun SG. Structurally Disordered Phosphorus-Doped Pt as a Highly Active Electrocatalyst for an Oxygen Reduction Reaction. ACS Catal 2020. [DOI: 10.1021/acscatal.0c03137] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Bang-An Lu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Lin-Fan Shen
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Jia Liu
- Shanghai Hydrogen Propulsion Technology Co., Ltd., Shanghai 201800, China
| | - Qinghua Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Li-Yang Wan
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - David J. Morris
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Rui-Xiang Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Zhi-You Zhou
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Gen Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Tian Sheng
- College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, China
| | - Lin Gu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Peng Zhang
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Na Tian
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Shi-Gang Sun
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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22
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Transport and Electrochemical Interface Properties of Ionomers in Low-Pt Loading Catalyst Layers: Effect of Ionomer Equivalent Weight and Relative Humidity. Molecules 2020; 25:molecules25153387. [PMID: 32722653 PMCID: PMC7435395 DOI: 10.3390/molecules25153387] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/02/2020] [Accepted: 07/18/2020] [Indexed: 11/17/2022] Open
Abstract
Catalyst layer (CL) ionomers control several transport and interfacial phenomena including long-range transport of protons, local transport of oxygen to Pt catalyst, effective utilization of Pt catalyst, electrochemical reaction kinetics and double-layer capacitance. In this work, the variation of these properties, as a function of humidity, for CLs made with two ionomers differing in side-chain length and equivalent weight, Nafion-1100 and Aquivion-825, was investigated. This is the first study to examine humidity-dependent oxygen reduction reaction (ORR) kinetics in-situ for CLs with different ionomers. A significant finding is the observation of higher ORR kinetic activity (A/cm2Pt) for the Aquivion-825 CL than for the Nafion-1100 CL. This is attributed to differences in the interfacial protonic concentrations at Pt/ionomer interface in the two CLs. The differences in Pt/ionomer interface is also noted in a higher local oxygen transport resistance for Aquivion-825 CLs compared to Nafion-1100 CLs, consistent with stronger interaction between ionomer and Pt for ionomer with more acid groups. Similar dependency on Pt utilization (ratio of electrochemically active area at any relative humidity (RH) to that at 100% RH) as a function of RH is observed for the two CLs. As expected, strong influence of humidity on proton conduction is observed. Amongst the two, the CL with high equivalent weight ionomer (Nafion-1100) exhibits higher conduction.
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23
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Li Y, Intikhab S, Malkani A, Xu B, Snyder J. Ionic Liquid Additives for the Mitigation of Nafion Specific Adsorption on Platinum. ACS Catal 2020. [DOI: 10.1021/acscatal.0c01243] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Yawei Li
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Saad Intikhab
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Arnav Malkani
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Bingjun Xu
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Joshua Snyder
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
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24
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Li Y, Van Cleve T, Sun R, Gawas R, Wang G, Tang M, Elabd YA, Snyder J, Neyerlin KC. Modifying the Electrocatalyst-Ionomer Interface via Sulfonated Poly(ionic liquid) Block Copolymers to Enable High-Performance Polymer Electrolyte Fuel Cells. ACS ENERGY LETTERS 2020; 5:1726-1731. [PMID: 38434232 PMCID: PMC10906942 DOI: 10.1021/acsenergylett.0c00532] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 03/05/2024]
Abstract
Polymer electrolyte membrane fuel cell (PEMFC) electrodes with a 0.07 mgPt cm-2 Pt/Vulcan electrocatalyst loading, containing only a sulfonated poly(ionic liquid) block copolymer (SPILBCP) ionomer, were fabricated and achieved a ca. 2× enhancement of kinetic performance through the suppression of Pt surface oxidation. However, SPILBCP electrodes lost over 70% of their electrochemical active area at 30% RH because of poor ionomer network connectivity. To combat these effects, electrodes made with a mix of Nafion/SPILBCP ionomers were developed. Mixed Nafion/SPILBCP electrodes resulted in a substantial improvement in MEA performance across the kinetic and mass transport-limited regions. Notably, this is the first time that specific activity values determined from an MEA were observed to be on par with prior half-cell results for Nafion-free Pt/Vulcan systems. These findings present a prospective strategy to improve the overall performance of MEAs fabricated with surface accessible electrocatalysts, providing a pathway to tailor the local electrocatalyst/ionomer interface.
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Affiliation(s)
- Yawei Li
- Chemistry
and Nanoscience Center, National Renewable
Energy Laboratory, Golden, Colorado 80401, United States
| | - Tim Van Cleve
- Chemistry
and Nanoscience Center, National Renewable
Energy Laboratory, Golden, Colorado 80401, United States
| | - Rui Sun
- Department
of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Ramchandra Gawas
- Department
of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Guanxiong Wang
- Chemistry
and Nanoscience Center, National Renewable
Energy Laboratory, Golden, Colorado 80401, United States
| | - Maureen Tang
- Department
of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - Yossef A. Elabd
- Department
of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States
| | - Joshua Snyder
- Department
of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
| | - K. C. Neyerlin
- Chemistry
and Nanoscience Center, National Renewable
Energy Laboratory, Golden, Colorado 80401, United States
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25
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Yang X, Zhang G, Du L, Zhang J, Chiang FK, Wen Y, Wang X, Wu Y, Chen N, Sun S. PGM-Free Fe/N/C and Ultralow Loading Pt/C Hybrid Cathode Catalysts with Enhanced Stability and Activity in PEM Fuel Cells. ACS APPLIED MATERIALS & INTERFACES 2020; 12:13739-13749. [PMID: 32130853 DOI: 10.1021/acsami.9b18085] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this work, the stability behaviors of the state-of-the-art Fe/N/C and Pt/C catalysts (as well as the activation time of the latter) were first systematically investigated, under different cathode catalyst loadings, in the membrane electrode assemblies (MEA) in PEM fuel cells. Based on that, two types of cathode electrodes with the combination of Fe/N/C and Pt/C catalysts were developed (type I: layered hybrid catalysts with Pt/C next to the membrane and type II: uniformly mixed catalysts). In this way, the shortcomings of the Fe/N/C catalyst (the fast decay) and the Pt/C catalyst (the long activation time) can be compensated at the same time. The hybrid catalysts also showed a very short activation time (a few hours vs over 10 h for Pt/C with the same Pt loading). Comparing the two types of hybrid catalysts, type I shows a much higher current density. The loadings of the Fe/N/C and Pt/C catalysts in the hybrid electrode were systematically studied, with optimal values of 1.0 mg cm-2 for Fe/N/C and 0.035 mgPt cm-2 for Pt/C. The Pt loading of this hybrid catalyst (type I) at the cathode only takes ca. 30% of the U.S. Department of Energy (DOE) target of Pt usage (0.100 mgPt cm-2), while its mass activity of Pt (in H2/O2 PEMFC) is 0.22 A mgPt-1 at 0.9iR-free V, reaching half of the DOE activity target (0.44 A mgPt-1), which is among the best performances reported so far. Via both half-cell and single-cell electrochemical evaluations together with other characterizations, the origin of the improved activity and stability is believed to be the synergistic effect between Pt/C and Fe/N/C catalysts to ORR. This work provides an effective strategy for engineering highly performing MEA for the industrialization of PEM fuel cells.
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Affiliation(s)
- Xiaohua Yang
- Institut National de la Recherche Scientifique-Énergie Matériaux et Télécommunications, Varennes, QC J3X 1S2, Canada
| | - Gaixia Zhang
- Institut National de la Recherche Scientifique-Énergie Matériaux et Télécommunications, Varennes, QC J3X 1S2, Canada
| | - Lei Du
- Institut National de la Recherche Scientifique-Énergie Matériaux et Télécommunications, Varennes, QC J3X 1S2, Canada
| | - Jun Zhang
- Institut National de la Recherche Scientifique-Énergie Matériaux et Télécommunications, Varennes, QC J3X 1S2, Canada
| | - Fu-Kuo Chiang
- National Institute of Low-Carbon-and-Clean-Energy, P.O. Box 001, Shenhua NICE, Future Science Park, Changping District, 102211 Beijing, China
| | - Yuren Wen
- School of Materials Science and Engineering, University of Science and Technology Beijing, 100083 Beijing, China
| | - Xiaomin Wang
- College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China
| | - Yucheng Wu
- College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China
| | - Ning Chen
- Canadian Light Source Inc., 44 Innovation Boulevard, Saskatoon, SK S7N 2 V3, Canada
| | - Shuhui Sun
- Institut National de la Recherche Scientifique-Énergie Matériaux et Télécommunications, Varennes, QC J3X 1S2, Canada
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26
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Van Cleve T, Khandavalli S, Chowdhury A, Medina S, Pylypenko S, Wang M, More KL, Kariuki N, Myers DJ, Weber AZ, Mauger SA, Ulsh M, Neyerlin KC. Dictating Pt-Based Electrocatalyst Performance in Polymer Electrolyte Fuel Cells, from Formulation to Application. ACS APPLIED MATERIALS & INTERFACES 2019; 11:46953-46964. [PMID: 31742376 DOI: 10.1021/acsami.9b17614] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In situ electrochemical diagnostics designed to probe ionomer interactions with platinum and carbon were applied to relate ionomer coverage and conformation, gleaned from anion adsorption data, with O2 transport resistance for low-loaded (0.05 mgPt cm-2) platinum-supported Vulcan carbon (Pt/Vu)-based electrodes in a polymer electrolyte fuel cell. Coupling the in situ diagnostic data with ex situ characterization of catalyst inks and electrode structures, the effect of ink composition is explained by both ink-level interactions that dictate the electrode microstructure during fabrication and the resulting local ionomer distribution near catalyst sites. Electrochemical techniques (CO displacement and ac impedance) show that catalyst inks with higher water content increase ionomer (sulfonate) interactions with Pt sites without significantly affecting ionomer coverage on the carbon support. Surprisingly, the higher anion adsorption is shown to have a minor impact on specific activity, while exhibiting a complex relationship with oxygen transport. Ex situ characterization of ionomer suspensions and catalyst/ionomer inks indicates that the lower ionomer coverage can be correlated with the formation of large ionomer aggregates and weaker ionomer/catalyst interactions in low-water content inks. These larger ionomer aggregates resulted in increased local oxygen transport resistance, namely, through the ionomer film, and reduced performance at high current density. In the water-rich inks, the ionomer aggregate size decreases, while stronger ionomer/Pt interactions are observed. The reduced ionomer aggregation improves transport resistance through the ionomer film, while the increased adsorption leads to the emergence of resistance at the ionomer/Pt interface. Overall, the high current density performance is shown to be a nonmonotonic function of ink water content, scaling with the local gas (H2, O2) transport resistance resulting from pore, thin film, and interfacial phenomena.
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Affiliation(s)
- Tim Van Cleve
- Chemistry and Nanoscience Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
| | - Sunilkumar Khandavalli
- Chemistry and Nanoscience Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
| | - Anamika Chowdhury
- Energy Conversion Group, Energy Technologies Area , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
- Department of Chemical and Biomolecular Engineering , University of California , Berkeley , California 94720 , United States
| | - Samantha Medina
- Colorado School of Mines , Golden , Colorado 80401 , United States
| | - Svitlana Pylypenko
- Chemistry and Nanoscience Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
- Colorado School of Mines , Golden , Colorado 80401 , United States
| | - Min Wang
- Chemistry and Nanoscience Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
| | - Karren L More
- Oak Ridge National Laboratory , Oak Ridge , Tennessee 37830 , United States
| | - Nancy Kariuki
- Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - Deborah J Myers
- Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - Adam Z Weber
- Energy Conversion Group, Energy Technologies Area , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Scott A Mauger
- Chemistry and Nanoscience Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
| | - Michael Ulsh
- Chemistry and Nanoscience Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
| | - K C Neyerlin
- Chemistry and Nanoscience Center , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
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