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Kaido Tammeveski - One of the best experts on this subject based on the ideXlab platform.

  • electrocatalysis of oxygen reduction on nitrogen containing multi walled carbon nanotube modified glassy carbon electrodes
    Electrochimica Acta, 2013
    Co-Authors: Merilin Vikkisk, Eugene Shulga, Ivar Kruusenberg, Urmas Joost, Kaido Tammeveski
    Abstract:

    Abstract The electrochemical reduction of oxygen was studied on nitrogen-doped multi-walled carbon nanotube (NCNT) modified glassy carbon (GC) electrodes employing the rotating disk electrode (RDE) method. Nitrogen doping was achieved by simple pyrolysis of the carbon nanotube material in the presence of urea. The surface morphology and composition of the NCNT samples were investigated by scanning Electron microscopy (SEM) and X-ray photoElectron spectroscopy (XPS). The SEM images revealed a rather uniform distribution of NCNTs on the GC electrode substrate. The XPS analysis showed a successful doping of carbon nanotubes with nitrogen species. The RDE results revealed that in alkaline solution the N-doped nanotube materials showed a remarkable electrocatalytic activity towards oxygen reduction. At low overpotentials the reduction of oxygen followed a two-Electron Pathway on undoped carbon nanotube modified GC electrodes, whereas on NCNT/GC electrodes a four-Electron Pathway of O 2 reduction predominated. The results obtained are significant for the development of nitrogen-doped carbon-based cathodes for alkaline membrane fuel cells.

  • electrocatalytic oxygen reduction on silver nanoparticle multi walled carbon nanotube modified glassy carbon electrodes in alkaline solution
    Electrochemistry Communications, 2012
    Co-Authors: Lauri Tammeveski, Väino Sammelselg, Heiki Erikson, Ave Sarapuu, Jekaterina Kozlova, Peeter Ritslaid, Kaido Tammeveski
    Abstract:

    Abstract The electrochemical reduction of oxygen was studied on Ag nanoparticle/multi-walled carbon nanotube (AgNP/MWCNT) nanocomposites in alkaline solution employing the rotating disk electrode (RDE) method. The composite material was prepared by sputter deposition of Ag catalyst on the surface of MWCNTs. The surface morphology of the AgNP/MWCNT composites was examined by scanning Electron microscopy (SEM). The SEM images show that there is a wide size distribution of Ag particles on MWCNTs. The RDE results reveal a high electrocatalytic activity of the AgNP/MWCNT nanocomposites towards the oxygen reduction reaction (ORR). On these catalysts the ORR proceeds by a four-Electron Pathway. The AgNP/MWCNT composite is a good catalyst for peroxide reduction. The results obtained are important for the development of Ag-based catalysts for alkaline membrane fuel cells.

Xiue Jiang - One of the best experts on this subject based on the ideXlab platform.

  • facile preparation of porous carbon nanosheets without template and their excellent electrocatalytic property
    ACS Applied Materials & Interfaces, 2013
    Co-Authors: Yichen Wang, Xiue Jiang
    Abstract:

    A novel porous carbon nanosheet was successfully fabricated by a one-step annealing process with folic acid as the carbon source in the absence of any other reagents or templates. The product exhibited a large specific surface area and good porosity. Meanwhile, the carbon nanosheets as a metal-free catalyst showed a high electrocatalytic activity toward the oxygen reduction reaction (ORR) in alkaline solution, including superior onset and reduction potentials as well as a nearly four-Electron Pathway.

  • facile green synthesis of nitrogen doped carbon supported ultrafine silver catalyst with enhanced electrocatalytic property
    Electrochimica Acta, 2013
    Co-Authors: Yichen Wang, Haibin Wu, Xiue Jiang
    Abstract:

    We have demonstrated a facile and green strategy to synthesize ultrafine silver nanoparticles monodispersed on N-doped three-dimensional carbon nanocloud surfaces without any toxic reagent. Folic acid was employed as the carbon precursor for forming N-doped carbon nanoflakes by a hydrothermal method. The as-prepared products can serve as both reducing agent and substrate, on which a high density of ultrafine Ag nanocrystals is stably grown in a homogeneously dispersive state spontaneously at room temperature. A feasible synthesis mechanism has been proposed by characterization of carbon precursor, nanomaterials composited without and with silver nanoparticles. It was found that the ethylenic and oxygenated groups led to the reduction process. The nanohybrids showed an enhanced electrocatalytic activity toward oxygen reduction reaction (ORR) in alkaline solution via a four-Electron Pathway. The catalyst also exhibited strong duration of methanol and good stability compared to commercial Pt/C catalysts. (C) 2013 Elsevier Ltd. All rights reserved.

  • facile green synthesis of nitrogen doped carbon supported ultrafine silver catalyst with enhanced electrocatalytic property
    Electrochimica Acta, 2013
    Co-Authors: Yichen Wang, Xiue Jiang
    Abstract:

    Abstract We have demonstrated a facile and green strategy to synthesize ultrafine silver nanoparticles monodispersed on N-doped three-dimensional carbon nanocloud surfaces without any toxic reagent. Folic acid was employed as the carbon precursor for forming N-doped carbon nanoflakes by a hydrothermal method. The as-prepared products can serve as both reducing agent and substrate, on which a high density of ultrafine Ag nanocrystals is stably grown in a homogeneously dispersive state spontaneously at room temperature. A feasible synthesis mechanism has been proposed by characterization of carbon precursor, nanomaterials composited without and with silver nanoparticles. It was found that the ethylenic and oxygenated groups led to the reduction process. The nanohybrids showed an enhanced electrocatalytic activity toward oxygen reduction reaction (ORR) in alkaline solution via a four-Electron Pathway. The catalyst also exhibited strong duration of methanol and good stability compared to commercial Pt/C catalysts.

Yichen Wang - One of the best experts on this subject based on the ideXlab platform.

  • facile preparation of porous carbon nanosheets without template and their excellent electrocatalytic property
    ACS Applied Materials & Interfaces, 2013
    Co-Authors: Yichen Wang, Xiue Jiang
    Abstract:

    A novel porous carbon nanosheet was successfully fabricated by a one-step annealing process with folic acid as the carbon source in the absence of any other reagents or templates. The product exhibited a large specific surface area and good porosity. Meanwhile, the carbon nanosheets as a metal-free catalyst showed a high electrocatalytic activity toward the oxygen reduction reaction (ORR) in alkaline solution, including superior onset and reduction potentials as well as a nearly four-Electron Pathway.

  • facile green synthesis of nitrogen doped carbon supported ultrafine silver catalyst with enhanced electrocatalytic property
    Electrochimica Acta, 2013
    Co-Authors: Yichen Wang, Haibin Wu, Xiue Jiang
    Abstract:

    We have demonstrated a facile and green strategy to synthesize ultrafine silver nanoparticles monodispersed on N-doped three-dimensional carbon nanocloud surfaces without any toxic reagent. Folic acid was employed as the carbon precursor for forming N-doped carbon nanoflakes by a hydrothermal method. The as-prepared products can serve as both reducing agent and substrate, on which a high density of ultrafine Ag nanocrystals is stably grown in a homogeneously dispersive state spontaneously at room temperature. A feasible synthesis mechanism has been proposed by characterization of carbon precursor, nanomaterials composited without and with silver nanoparticles. It was found that the ethylenic and oxygenated groups led to the reduction process. The nanohybrids showed an enhanced electrocatalytic activity toward oxygen reduction reaction (ORR) in alkaline solution via a four-Electron Pathway. The catalyst also exhibited strong duration of methanol and good stability compared to commercial Pt/C catalysts. (C) 2013 Elsevier Ltd. All rights reserved.

  • facile green synthesis of nitrogen doped carbon supported ultrafine silver catalyst with enhanced electrocatalytic property
    Electrochimica Acta, 2013
    Co-Authors: Yichen Wang, Xiue Jiang
    Abstract:

    Abstract We have demonstrated a facile and green strategy to synthesize ultrafine silver nanoparticles monodispersed on N-doped three-dimensional carbon nanocloud surfaces without any toxic reagent. Folic acid was employed as the carbon precursor for forming N-doped carbon nanoflakes by a hydrothermal method. The as-prepared products can serve as both reducing agent and substrate, on which a high density of ultrafine Ag nanocrystals is stably grown in a homogeneously dispersive state spontaneously at room temperature. A feasible synthesis mechanism has been proposed by characterization of carbon precursor, nanomaterials composited without and with silver nanoparticles. It was found that the ethylenic and oxygenated groups led to the reduction process. The nanohybrids showed an enhanced electrocatalytic activity toward oxygen reduction reaction (ORR) in alkaline solution via a four-Electron Pathway. The catalyst also exhibited strong duration of methanol and good stability compared to commercial Pt/C catalysts.

Yuanhang Cheng - One of the best experts on this subject based on the ideXlab platform.

  • ag nanoparticles on boron doped multi walled carbon nanotubes as a synergistic catalysts for oxygen reduction reaction in alkaline media
    Electrochimica Acta, 2015
    Co-Authors: Yuanhang Cheng, Yayuan Tian, Saiwing Tsang, Chuanwei Yan
    Abstract:

    Abstract Here we report the oxygen reduction reaction (ORR) activity of Ag nanoparticles supported on boron doped multi-walled carbon nanotubes (Ag/B-MWCNTs) with different Ag loadings synthesized by a facile chemical method. Transmission Electron microscopy (TEM) and X-ray diffraction patterns (XRD) measurements were employed to investigate the morphology and crystal structure of the as-prepared catalysts. The electrochemical results demonstrated that all the Ag/B-MWCNTs samples catalyzed the ORR in alkaline media by an efficient four-Electron Pathway. Furthermore, Ag/B-MWCNTs with lowest Ag loading (20%) performed the highest mass activity towards ORR mainly due to the synergistic effect of Ag nanoparticles and B-MWCNTs. This work brings insight into the role of supporting materials in reducing the loading of metal catalyst towards low-cost ORR in alkaline media.

  • boron doped multi walled carbon nanotubes as catalysts for oxygen reduction reaction and oxygen evolution reactionin in alkaline media
    Electrochimica Acta, 2014
    Co-Authors: Yuanhang Cheng, Yayua Tia, Jianguo Liu
    Abstract:

    Abstract The boron doped multi-walled carbon nanotubes (B-MWCNTs) were synthesized by thermal annealing multi-walled carbon nanotubes (MWCNTs) in the presence of boric acid. The transmission Electron microscopy (TEM) and X-ray diffraction (XRD) results revealed that the structure of MWCNTs does not be destroyed during the doping process, and X-ray photoElectron spectroscopy (XPS) analysis demonstrated the boron atoms were successfully doped in the structure of MWCNTs. The electrocatalytic properties of B-MWCNTs are characterized by rotating disk electrode (RDE) methods. The results demonstrated that the B-MWCNTs catalyzed oxygen reduction reaction (ORR) in alkaline media by a 2 + 2 Electron Pathway and it showed good catalytic activity for oxygen evolution reaction (OER) as well.

Jianguo Liu - One of the best experts on this subject based on the ideXlab platform.

  • boron doped multi walled carbon nanotubes as catalysts for oxygen reduction reaction and oxygen evolution reactionin in alkaline media
    Electrochimica Acta, 2014
    Co-Authors: Yuanhang Cheng, Yayua Tia, Jianguo Liu
    Abstract:

    Abstract The boron doped multi-walled carbon nanotubes (B-MWCNTs) were synthesized by thermal annealing multi-walled carbon nanotubes (MWCNTs) in the presence of boric acid. The transmission Electron microscopy (TEM) and X-ray diffraction (XRD) results revealed that the structure of MWCNTs does not be destroyed during the doping process, and X-ray photoElectron spectroscopy (XPS) analysis demonstrated the boron atoms were successfully doped in the structure of MWCNTs. The electrocatalytic properties of B-MWCNTs are characterized by rotating disk electrode (RDE) methods. The results demonstrated that the B-MWCNTs catalyzed oxygen reduction reaction (ORR) in alkaline media by a 2 + 2 Electron Pathway and it showed good catalytic activity for oxygen evolution reaction (OER) as well.