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Favero S, Li A, Wang M, Uddin F, Kuzuoglu B, Georgeson A, Stephens IEL, Titirici MM. Poly(ionic liquid) Ionomers Help Prevent Active Site Aggregation, in Single-Site Oxygen Reduction Catalysts. ACS Catal 2024; 14:7937-7948. [PMID: 38779182 PMCID: PMC11106738 DOI: 10.1021/acscatal.4c01418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 04/30/2024] [Accepted: 04/30/2024] [Indexed: 05/25/2024]
Abstract
Anion exchange membrane fuel cells (AEMFCs) can produce clean electricity without the need for platinum-group metals at the cathode. To improve their durability and performance, most research investigations so far have focused on optimizing the catalyst and anion exchange membrane, while few studies have been dedicated to the effect of the ionomer. Herein, we address this gap by developing a poly(ionic liquid)-based ionomer and studying its effect on oxygen transport and oxygen reduction kinetics, in comparison to the commercial proton exchange and anion exchange ionomers Nafion and Fumion. Our study shows that the choice of ionomer has a dramatic effect on the morphology of the catalyst layer, in particular on iron aggregation. We also observed that the quality of the catalyst layer and the degree of iron aggregation can be correlated to the rheological properties of the catalyst ink. Moreover, this work highlights the impact of the ionomer on the resistance to oxygen transport and reports improved oxygen diffusion compared to Nafion, for poly(ionic liquid)s with fluorinated anions. Finally, the performance of the catalyst-ionomer layer for oxygen reduction was tested with a rotating disc electrode (RDE) and a gas diffusion electrode (GDE). We observed dramatic differences between the two configurations, which we attribute to the different morphologies of the catalyst layer. In summary, our study highlights the dramatic and overlooked effect of the ionomer and the limitations of the RDE in predicting fuel cell performance.
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Affiliation(s)
- Silvia Favero
- Department
of Chemical Engineering, Imperial College
London, SW7 2AZ London, U.K.
| | - Alain Li
- Department
of Chemical Engineering, Imperial College
London, SW7 2AZ London, U.K.
| | - Mengnan Wang
- Department
of Chemical Engineering, Imperial College
London, SW7 2AZ London, U.K.
| | - Fayyad Uddin
- Department
of Chemical Engineering, Imperial College
London, SW7 2AZ London, U.K.
| | - Bora Kuzuoglu
- Department
of Chemical Engineering, Imperial College
London, SW7 2AZ London, U.K.
| | - Arthur Georgeson
- Department
of Chemical Engineering, Imperial College
London, SW7 2AZ London, U.K.
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Liaqat M, Kankanamage RNT, Duan H, Shimogawa R, Sun J, Nielsen M, Shaaban E, Zhu Y, Gao P, Rusling JF, Frenkel AI, He J. Single-Atom Cobalt Catalysts Coupled with Peroxidase Biocatalysis for C-H Bond Oxidation. ACS APPLIED MATERIALS & INTERFACES 2023; 15:40343-40354. [PMID: 37590263 DOI: 10.1021/acsami.3c03053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/19/2023]
Abstract
This paper reports a robust strategy to catalyze in situ C-H oxidation by combining cobalt (Co) single-atom catalysts (SACs) and horseradish peroxidase (HRP). Co SACs were synthesized using the complex of Co phthalocyanine with 3-propanol pyridine at the two axial positions as the Co source to tune the coordination environment of Co by the stepwise removal of axial pyridine moieties under thermal annealing. These structural features of Co sites, as confirmed by infrared and X-ray absorption spectroscopy, were strongly correlated to their reactivity. All Co catalysts synthesized below 300 °C were inactive due to the full coordination of Co sites in octahedral geometry. Increasing the calcination temperature led to an improvement in catalytic activity for reducing O2, although molecular Co species with square planar coordination obtained below 600 °C were less selective to reduce O2 to H2O2 through the two-electron pathway. Co SACs obtained at 800 °C showed superior activity in producing H2O2 with a selectivity of 82-85% in a broad potential range. In situ production of H2O2 was further coupled with HRP to drive the selective C-H bond oxidation in 2-naphthol. Our strategy provides new insights into the design of highly effective, stable SACs for selective C-H bond activation when coupled with natural enzymes.
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Affiliation(s)
- Maham Liaqat
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | | | - Hanyi Duan
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Ryuichi Shimogawa
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11790, United States
| | - Jiyu Sun
- Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Monia Nielsen
- Department of Materials Science and Engineering, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Ehab Shaaban
- Department of Chemistry, University of New Hampshire, Durham, New Hampshire 03824, United States
| | - Yuanyuan Zhu
- Department of Materials Science and Engineering, University of Connecticut, Storrs, Connecticut 06269, United States
- Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Puxian Gao
- Department of Materials Science and Engineering, University of Connecticut, Storrs, Connecticut 06269, United States
- Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269, United States
| | - James F Rusling
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
- Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269, United States
- Department of Surgery and Neag Cancer Center, Uconn Health, Farmington, Connecticut 06030, United States
- School of Chemistry, National University of Ireland at Galway, Galway H91 TK33, Ireland
| | - Anatoly I Frenkel
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11790, United States
- Division of Chemistry, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Jie He
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
- Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269, United States
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Patra S, Purohit SS, Swain SK. In vivo fluorescence non-enzymatic glucose sensing technique for diabetes management by CQDs incorporated dextran nanocomposites in human blood serums. Microchem J 2023. [DOI: 10.1016/j.microc.2023.108646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
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