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Copolymer-Induced Intermolecular Charge Transfer: Enhancing the Activity of Metal-Free Catalysts for Oxygen Reduction |
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| Authors: | Yihuan Yu Prof Zhengping Zhang Prof Liming Dai Prof Feng Wang |
| Institution: | 1. State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and Technology, for Materials, Beijing University of Chemical Technology, Beijing, 100029 P. R. China
Beijing Advanced Innovation Center for Soft Matter Science and, Engineering, College of Energy, Beijing University of, Chemical Technology, Beijing, 100029 P. R. China;2. State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and Technology, for Materials, Beijing University of Chemical Technology, Beijing, 100029 P. R. China;3. Beijing Advanced Innovation Center for Soft Matter Science and, Engineering, College of Energy, Beijing University of, Chemical Technology, Beijing, 100029 P. R. China |
| Abstract: | Breaking the electroneutrality of sp2 carbon lattice is a viable way for nanocarbon material to modulate the charge delocalization and to further alter the electrocatalytic activity. Positive charge spreadsheeting is preferable for catalyzing the oxygen reduction reaction (ORR) and other electrochemical reactions. Analogously to the case of intramolecular charge transfer by heteroatom doping, electrons in the conjugated carbon lattice can be redistributed by the intermolecular charge transfer from the nanocarbon material to the polyelectrolyte. A copolymeric electrolyte, epichlorohydrin-dimethylamine copolymer (EDC) was synthesized. The EDC-modified carbon nanotube (CNT) hybrid was subsequently fabricated by sonication treatment and served as a metal-free carbonaceous electrocatalyst with remarkable catalytic activity and stability. The resultant hybrid presents positive charge spreadsheeting on CNT as a result of the interfacial electron transfer from CNT to EDC. DFT calculations were further carried out to reveal that the enhancement of the wrapped EDC polyelectrolyte originates from the synergetic effect of the quaternary ammonium-hydroxyl covalently bonded structure. The CNT-EDC hybrid not only provides an atomically precise regulation to modulate nanocarbon materials from inactive carbonaceous materials into efficient metal-free catalysts, but it also opens new avenues to develop metal-free catalysts with well-defined and highly active sites. |
| Keywords: | charge transfer metal-free electrocatalysts nanotubes oxygen reduction reaction polyelectrolytes |