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Tong Huang Haifei Jiang John C. Douglin Yu Chen Shuoyao Yin Dr. Junfeng Zhang Xiaojuan Deng Prof. Hong Wu Prof. Yan Yin Prof. Dario R. Dekel Prof. Michael D. Guiver Prof. Zhongyi Jiang 《Angewandte Chemie (International ed. in English)》2023,62(4):e202209306
Covalent organic framework nanosheets (COF-NSs) are emerging building blocks for functional materials, and their scalable fabrication is highly desirable. Current synthetic methods suffer from low volume yields resulting from confined on-surface/at-interface growth space and complex multiple-phase synthesis systems. Herein, we report the synthesis of charged COF-NSs in open space using a single-phase organic solution system, achieving magnitudes higher volume yields of up to 18.7 mg mL−1. Charge-induced electrostatic repulsion forces enable in-plane anisotropic secondary growth from initial discrete and disordered polymers into large and crystalline COF-NSs. The charged COF-NS colloidal suspensions are cast into thin and compact proton exchange membranes (PEMs) with lamellar morphology and oriented crystallinity, displaying outstanding proton conductivity, negligible dimensional swelling, and good H2/O2 fuel cell performance. 相似文献
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Douglin John C. Singh Ramesh K. Hamo Eliran R. Hassine Mohamad B. Ferreira Paulo J. Rosen Brian A. Miller Hamish A. Rothenberg Gadi Dekel Dario R. 《Journal of Solid State Electrochemistry》2022,26(9):2049-2057
Journal of Solid State Electrochemistry - This study focuses on H2-O2 operando AEMFC performance based on several platinum group metal (PGM) and PGM-free catalysts. Specifically, we evaluate the... 相似文献
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Kanika Aggarwal Saja Bsoul John C. Douglin Songlin Li Prof. Dario R. Dekel Prof. Charles E. Diesendruck 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(7):e202103744
Anion-exchange membrane fuel cells (AEMFCs) are promising energy conversion devices due to their high efficiency. Nonetheless, AEMFC operation time is currently limited by the low chemical stability of their polymeric anion-exchange membranes. In recent years, metallopolymers, where the metal centers assume the ion transport function, have been proposed as a chemically stable alternative. Here we present a systematic study using a polymer backbone with side-chain N-heterocyclic carbene (NHC) ligands complexed to various metals with low oxophilicity, such as copper, zinc, nickel, and gold. The golden metallopolymer, using the metal with the lowest oxophilicity, demonstrates exceptional alkaline stability, far superior to state-of-the-art quaternary ammonium cations, as well as good in situ AEMFC results. These results demonstrate that judiciously designed metallopolymers may be superior to purely organic membranes and provides a scientific base for further developments in the field. 相似文献
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Praats Reio Käärik Maike Kikas Arvo Kisand Vambola Aruväli Jaan Paiste Päärn Merisalu Maido Sarapuu Ave Leis Jaan Sammelselg Väino Douglin John C. Dekel Dario R. Tammeveski Kaido 《Journal of Solid State Electrochemistry》2021,25(1):57-71
Journal of Solid State Electrochemistry - In this work, composite materials based on carbide-derived carbon (CDC) and carbon nanotubes (CNT) modified with Co phthalocyanine (CoPc) were employed as... 相似文献
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Aniket Raut Haoyan Fang Yu-Chung Lin Shi Fu David Sprouster Ryuichi Shimogawa Anatoly I. Frenkel Chulsung Bae John C. Douglin Jaana Lillojad Kaido Tammeveski Zhiqiao Zeng Stoyan Bliznakov Miriam Rafailovich Dario R. Dekel 《Angewandte Chemie (International ed. in English)》2023,62(37):e202306754
Despite the recent progress in increasing the power generation of Anion-exchange membrane fuel cells (AEMFCs), their durability is still far lower than that of Proton exchange membrane fuel cells (PEMFCs). Using the complementary techniques of X-ray micro-computed tomography (CT), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) spectroscopy, we have identified Pt ion migration as an important factor to explain the decay in performance of AEMFCs. In alkaline media Pt+2 ions are easily formed which then either undergo dissolution into the carbon support or migrate to the membrane. In contrast to PEMFCs, where hydrogen cross over reduces the ions forming a vertical “Pt line” within the membrane, the ions in the AEM are trapped by charged groups within the membrane, leading to disintegration of the membrane and failure. Diffusion of the metal components is still observed when the Pt/C of the cathode is substituted with a FeCo−N−C catalyst, but in this case the Fe and Co ions are not trapped within the membrane, but rather migrate into the anode, thereby increasing the stability of the membrane. 相似文献
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