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7.15】Prof. Liming Dai
题目:Carbon Nanomaterials as Metal-free Catalysts for Energy Conversion
 
2014-07-09 | 文章来源:先进炭材料研究部        【 】【打印】【关闭

题目:Carbon Nanomaterials as Metal-free Catalysts for Energy Conversion

报告人:Prof. Liming Dai (Case Western Reserve University, USA)

时间:715日(周二)10:30-11:45

地点:李薰楼468会议室

报告摘要Oxygen reduction reaction (ORR) is an important process in many fields, including energy conversion (fuel cells, metal-air batteries), corrosion, and biosensing. Although Pt nanoparticles have been regarded as the best electrocatalyst for ORR in fuel cells, they are still suffered from multiple problems. For instance, Pt-based cathode electrocatalysts are susceptible to the cross-over effect, long-term instability, and CO poisoning. Furthermore, the high cost of Pt, together with its limited reserve in nature, has been shown to be the “bottleneck” for large-scale commercialization of the fuel cell technology.

Along with the recent intensive research efforts in reducing or replacing Pt-based electrode in fuel cells, we have previously demonstrated that vertically aligned nitrogen-doped carbon nanotubes (VA-NCNTs) produced by pyrolysis of iron (II) phthalocyanine could actively catalyze ORR via a four-electron process free from the crossover and CO poisoning effects with a 3-time higher electrocatalytic activity and better long-term durability than that of commercially available Pt/C electrocatalysts. Similar ORR electrocatalytic activity was also observed for nitrogen-doped graphene (N-graphene). On the basis of these experimental observations and quantum mechanics calculations, we have attributed the observed ORR catalytic activities of the VA-NCNTs and N-graphene to the electron-accepting ability of the chemically-bonded nitrogen atoms, which create a net positive charge (via intramolecular charge-transfer) on adjacent carbon atoms in the nanocarbon structures to readily attract electrons from the anode for facilitating the O2 adsorption and ORR on the cathode. These findings prompted us to develop carbon-based metal-free ORR catalysts by positively charging carbon atoms in the nitrogen-free carbon nanotubes and graphene plane through intermolecular charge-transfer with functionalized/adsorbed moieties. In particular, we have recently used poly(diallyldimethylammonium chloride), PDDA, as an electron acceptor for functionalizing N-free carbon nanotubes and graphene to show remarkable electrocatalytic activity toward ORR. We have also demonstrated that carbon nanotubes and graphene co-doped with N and B showed a synergetic effect toward ORR, and that nitrogen-doped 3D graphene foam (N-GF) could be used as a metal-free electrocatalyst for the reduction of triiodide to replace the Pt cathode in dye-sensitized solar cells (DSSCs). In this talk, we will summarize some of our work on the metal-free ORR catalysts based on carbon nanomaterials, along with an overview on the recent developments in this exciting field.

Liming Dai, Ph.D.

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Liming Dai is the Kent Hale Smith Professor in the Department of Macromolecular Science and Engineering at Case Western Reserve University (CWRU). He is also director of the Center of Advanced Science and Engineering for Carbon (CASE4Carbon). Before joining the CWRU, he was an associate professor of polymer engineering at the University of Akron and the Wright Brothers Institute Endowed Chair Professor of Nanomaterials at the University of Dayton. He is a Fellow of the Royal Society of Chemistry and Fellow of the American Institute for Medical and Biological Engineering (AIMBE). Dr. Dai’s expertise lies across the synthesis, chemical modification and device fabrication of conjugated polymers and carbon nanomaterials for energy-related and biomedical applications. He has published over 300 scientific papers, a research monograph on intelligent macromolecules, an edited book on carbon nanotechnology, and held about 30 issued/applied patents. His h-index: 68; Citations: > 15,000 (Source: ISI Web of KnowledgeSM; Author query: “Dai LM” and “Dai L)

Liming Dai can be reached at: Department of Macromolecular Science and Engineering, Case School of Engineering, Case Western Reserve University, Cleveland, OH44106 USA

E-mail: liming.dai@case.edu

http://case.edu/cse/eche/daigroup/index.html

http://polymers.case.edu/

 

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