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Ei Phyu Win P, Yang J, Ning S, Huang X, Fu G, Sun Q, Xia XH, Wang J. Molecular architectures of iron complexes for oxygen reduction catalysis-Activity enhancement by hydroxide ions coupling. Proc Natl Acad Sci U S A 2024; 121:e2316553121. [PMID: 38437553 PMCID: PMC10945836 DOI: 10.1073/pnas.2316553121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Accepted: 12/28/2023] [Indexed: 03/06/2024] Open
Abstract
Developing cost-effective and high-performance electrocatalysts for oxygen reduction reaction (ORR) is critical for clean energy generation. Here, we propose an approach to the synthesis of iron phthalocyanine nanotubes (FePc NTs) as a highly active and selective electrocatalyst for ORR. The performance is significantly superior to FePc in randomly aggregated and molecularly dispersed states, as well as the commercial Pt/C catalyst. When FePc NTs are anchored on graphene, the resulting architecture shifts the ORR potentials above the redox potentials of Fe2+/3+ sites. This does not obey the redox-mediated mechanism operative on conventional FePc with a Fe2+-N moiety serving as the active sites. Pourbaix analysis shows that the redox of Fe2+/3+ sites couples with HO- ions transfer, forming a HO-Fe3+-N moiety serving as the ORR active sites under the turnover condition. The chemisorption of ORR intermediates is appropriately weakened on the HO-Fe3+-N moiety compared to the Fe2+-N state and thus is intrinsically more ORR active.
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Affiliation(s)
- Poe Ei Phyu Win
- Innovation Center for Chemical Science, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou215006, China
| | - Jiahui Yang
- Innovation Center for Chemical Science, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou215006, China
| | - Shuwang Ning
- Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing210023, China
| | - Xiang Huang
- Department of Physics, Southern University of Science and Technology, Shenzhen518055, China
| | - Gengtao Fu
- Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing210023, China
| | - Qiming Sun
- Innovation Center for Chemical Science, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou215006, China
- Jiangsu Key Laboratory of Advanced Negative Carbon Technologies, Soochow University, Suzhou, Jiangsu215123, China
| | - Xing-Hua Xia
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing210023, China
| | - Jiong Wang
- Innovation Center for Chemical Science, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou215006, China
- Jiangsu Key Laboratory of Advanced Negative Carbon Technologies, Soochow University, Suzhou, Jiangsu215123, China
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Phan AD. Screening and collective effects in randomly pinned fluids: a new theoretical framework. J Phys Condens Matter 2022; 34:435101. [PMID: 35985315 DOI: 10.1088/1361-648x/ac8b51] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 08/19/2022] [Indexed: 06/15/2023]
Abstract
We propose a theoretical framework for the dynamics of bulk isotropic hard-sphere systems in the presence of randomly pinned particles and apply this theory to supercooled water to validate it. Structural relaxation is mainly governed by local and non-local activated process. As the pinned fraction grows, a local caging constraint becomes stronger and the long range collective aspect of relaxation is screened by immobile obstacles. Different responses of the local and cooperative motions results in subtle predictions for how the alpha relaxation time varies with pinning and density. Our theoretical analysis for the relaxation time of water with pinned molecules quantitatively well describe previous simulations. In addition, the thermal dependence of relaxation for unpinned bulk water is also consistent with prior computational and experimental data.
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Affiliation(s)
- Anh D Phan
- Faculty of Materials Science and Engineering, Phenikaa Institute for Advanced Study, Phenikaa University, Hanoi 12116, Vietnam
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Xu Y, Hu H, Chen W, Suo P, Zhang Y, Zhang S, Xu H. Phononic Cavity Optomechanics of Atomically Thin Crystal in Plasmonic Nanocavity. ACS Nano 2022; 16:12711-12719. [PMID: 35867404 DOI: 10.1021/acsnano.2c04478] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In the picture of molecular cavity optomechanics, surface-enhanced Raman scattering (SERS) can be understood as molecular oscillators parametrically coupled to plasmonic nanocavities supporting an extremely localized optical field. This enables SERS from conventional fingerprint detection toward quantum nanotechnologies associated with, e.g., frequency upconversion and optomechanically induced transparency. Here, we study a phononic cavity optomechanical system consisting of a monolayer MoS2 placed inside a plasmonic nanogap, where the coherent phonon-plasmon interaction involves the collective oscillation from tens of thousands of unit cells of the MoS2 crystal. We observe the selective nonlinear SERS enhancement of the system as determined by the laser-plasmon detuning, suggesting the dynamic backaction modification of the phonon populations. Anomalous superlinear power dependence of a second-order Raman-inactive phonon mode with respect to the first-order phonons is also observed, indicating the distinctive properties of the phononic nanodevice compared with the molecular system. Our results promote the development of robust phononic optomechanical nanocavities to further explore the related quantum correlation and nonlinear effects including parametric instabilities.
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Affiliation(s)
- Yuhao Xu
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
| | - Huatian Hu
- The Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Wen Chen
- Ecole Polytechnique Fédérale de Lausanne, Institute of Physics, Lausanne CH-1015, Switzerland
| | - Pengfei Suo
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
| | - Yuan Zhang
- Henan Key Laboratory of Diamond Optoelectronic Materials and Devices, Key Laboratory of Material Physics, Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450052, China
| | - Shunping Zhang
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
- Wuhan Institute of Quantum Technology, Wuhan 430206, China
| | - Hongxing Xu
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
- Wuhan Institute of Quantum Technology, Wuhan 430206, China
- School of Microelectronics, Wuhan University, Wuhan 430072, China
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Fragkopoulos AA, Vachier J, Frey J, Le Menn FM, Mazza MG, Wilczek M, Zwicker D, Bäumchen O. Self-generated oxygen gradients control collective aggregation of photosynthetic microbes. J R Soc Interface 2021; 18:20210553. [PMID: 34847792 PMCID: PMC8633776 DOI: 10.1098/rsif.2021.0553] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
For billions of years, photosynthetic microbes have evolved under the variable exposure to sunlight in diverse ecosystems and microhabitats all over our planet. Their abilities to dynamically respond to alterations of the luminous intensity, including phototaxis, surface association and diurnal cell cycles, are pivotal for their survival. If these strategies fail in the absence of light, the microbes can still sustain essential metabolic functionalities and motility by switching their energy production from photosynthesis to oxygen respiration. For suspensions of motile C. reinhardtii cells above a critical density, we demonstrate that this switch reversibly controls collective microbial aggregation. Aerobic respiration dominates over photosynthesis in conditions of low light, which causes the microbial motility to sensitively depend on the local availability of oxygen. For dense microbial populations in self-generated oxygen gradients, microfluidic experiments and continuum theory based on a reaction–diffusion mechanism show that oxygen-regulated motility enables the collective emergence of highly localized regions of high and low cell densities.
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Affiliation(s)
- Alexandros A Fragkopoulos
- Max Planck Institute for Dynamics and Self-Organization (MPIDS), Am Faßberg 17, 37077 Göttingen, Germany
| | - Jérémy Vachier
- Max Planck Institute for Dynamics and Self-Organization (MPIDS), Am Faßberg 17, 37077 Göttingen, Germany.,Nordita, KTH Royal Institute of Technology and Stockholm University, Hannes Alfvéns väg 12, 106 91 Stockholm, Sweden
| | - Johannes Frey
- Max Planck Institute for Dynamics and Self-Organization (MPIDS), Am Faßberg 17, 37077 Göttingen, Germany
| | - Flora-Maud Le Menn
- Max Planck Institute for Dynamics and Self-Organization (MPIDS), Am Faßberg 17, 37077 Göttingen, Germany
| | - Marco G Mazza
- Max Planck Institute for Dynamics and Self-Organization (MPIDS), Am Faßberg 17, 37077 Göttingen, Germany.,Interdisciplinary Centre for Mathematical Modelling and Department of Mathematical Sciences, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK
| | - Michael Wilczek
- Max Planck Institute for Dynamics and Self-Organization (MPIDS), Am Faßberg 17, 37077 Göttingen, Germany
| | - David Zwicker
- Max Planck Institute for Dynamics and Self-Organization (MPIDS), Am Faßberg 17, 37077 Göttingen, Germany
| | - Oliver Bäumchen
- Max Planck Institute for Dynamics and Self-Organization (MPIDS), Am Faßberg 17, 37077 Göttingen, Germany.,Experimental Physics V, University of Bayreuth, Universitätsstr. 30, 95447 Bayreuth, Germany
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Nagaoka R, Bane KLF. Collective effects in a diffraction-limited storage ring. J Synchrotron Radiat 2014; 21:937-960. [PMID: 25177983 DOI: 10.1107/s1600577514015215] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 06/28/2014] [Indexed: 06/03/2023]
Abstract
This paper gives an overview of collective effects that are likely to appear and possibly limit the performance in a diffraction-limited storage ring (DLSR) that stores a high-intensity ultra-low-emittance beam. Beam instabilities and other intensity-dependent effects that may significantly impact the machine performance are covered. The latter include beam-induced machine heating, Touschek scattering, intra-beam scattering, as well as incoherent tune shifts. The general trend that the efforts to achieve ultra-low emittance result in increasing the machine coupling impedance and the beam sensitivity to instability is reviewed. The nature of coupling impedance in a DLSR is described, followed by a series of potentially dangerous beam instabilities driven by the former, such as resistive-wall, TMCI (transverse mode coupling instability), head-tail and microwave instabilities. In addition, beam-ion and CSR (coherent synchrotron radiation) instabilities are also treated. Means to fight against collective effects such as lengthening of the bunch with passive harmonic cavities and bunch-by-bunch transverse feedback are introduced. Numerical codes developed and used to evaluate the machine coupling impedance, as well as to simulate beam instability using the former as inputs are described.
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Affiliation(s)
| | - Karl L F Bane
- SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94309, USA
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