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Porous VO(x)N(y) nanoribbons supported on CNTs as efficient and stable non-noble electrocatalysts for the oxygen reduction reaction.

Huang K, Bi K, Lu YK, Zhang R, Liu J, Wang WJ, Tang HL, Wang YG, Lei M - Sci Rep (2015)

Bottom Line: Novel nanocomposites of carbon nanotubes supported porous VO(x)N(y) nonoribbons (VO(x)N(y)-CNTs) have been synthesized by the annealing of the sol-gel mixture of CNTs and V2O5 under NH3 atmosphere as well as the ageing process in air.Besides the morphological and structural characterizations revealed by TEM, SEAD, EDS, XRD and XPS measurements, typical electrochemical tests including cyclic voltammetry (CV), rotating disk electrode (RDE) and chronoamperometry have been employed to determine the oxygen reduction reaction (ORR) performance of VO(x)N(y)-CNTs.Therefore, we have reasonable grounds to believe that this new VO(x)N(y)-CNTs nanocomposites can be regarded as a promising non-precious methanol-tolerant ORR catalyst candidate for alkaline fuel cells.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Information Photonics and Optical Communications &School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China.

ABSTRACT
Novel nanocomposites of carbon nanotubes supported porous VO(x)N(y) nonoribbons (VO(x)N(y)-CNTs) have been synthesized by the annealing of the sol-gel mixture of CNTs and V2O5 under NH3 atmosphere as well as the ageing process in air. Besides the morphological and structural characterizations revealed by TEM, SEAD, EDS, XRD and XPS measurements, typical electrochemical tests including cyclic voltammetry (CV), rotating disk electrode (RDE) and chronoamperometry have been employed to determine the oxygen reduction reaction (ORR) performance of VO(x)N(y)-CNTs. Inspiringly, the results indicate that VO(x)N(y)-CNTs catalyst exhibits a 0.4 mA/cm(2) larger diffusion-limited current density, a 0.10  V smaller onset potential value, a 10.73% less of ORR current decay and an excellent methanol-tolerance compared with commercial Pt/C catalyst. Therefore, we have reasonable grounds to believe that this new VO(x)N(y)-CNTs nanocomposites can be regarded as a promising non-precious methanol-tolerant ORR catalyst candidate for alkaline fuel cells.

No MeSH data available.


Related in: MedlinePlus

ORR activities of different VOxNy-based catalysts compared with Pt/C catalyst at 1600 rpm.
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f5: ORR activities of different VOxNy-based catalysts compared with Pt/C catalyst at 1600 rpm.

Mentions: The ORR performances of VOxNy and VOxNy-CNTs catalysts with VOxNy-XC 72R and commercial Pt/C as the references have been further investigated in alkaline electrolyte. As shown in Fig. 5, the ORR polarization curves for all kinds of catalysts at 1600 rpm in O2-saturated 0.1 M KOH exhibit a combined kinetic-diffusion control of charge transfer and mass transport process at different potentials. It is obvious that the support of carbon can improve the onset potential, half-wave potential and the diffusion-limited current density of pure VOxNy nanoribbons catalyst, and the hybrid with CNTs displays the strongest competitiveness with respect to the commercial Pt/C. Although the onset potential (0.88 V Vs. RHE) and half-wave potential (0.77 V Vs. RHE) of VOxNy-CNTs are 0.10 and 0.07 V smaller than those of Pt/C electrode, the diffusion-limited current density is about 0.4 mA/cm2 larger. Meanwhile, the stabilities of VOxNy-based electrodes are quite superior to that of Pt/C electrode no matter whether adding 3M Methanol at 500 s. As shown in the inset of Fig. 6, the current densities of pure VOxNy electrode, VOxNy-Xc 72R electrode, VOxNy-CNTs electrode and Pt/C electrode remain 98.73%, 89.76%, 93.68% and 82.95% after 1000 s compared with the initial ones. The increased loss with the addition of XC 72R and CNTs can be attributed to the oxidation of carbon under dynamic potential conditions and high-oxygen environment3940. Furthermore, unlike the instantaneous current density jump for Pt/C electrode due to the addition and the following electro-oxidation of methanol41, all VOxNy-based electrodes exhibit superior methanol tolerance with negligible changes. In addition, the ORR performance in alkaline electrolyte of VOxNy-CNTs is also highly comparable to other widely studied non-precious electrocatalysts, such as 3D nitrogen-doped graphene aerogel-supported Fe3O4 nanoparticles (Fe3O4/N-GAs)42, carbon nanotubes supported MnOx hybrids (MnOx/CNTs)43, carbon-supported CoSe2 nanocatalyst (CoSe2/C)44, cobalt and nitrogen-cofunctionalized graphene (Co-N-GN)45 and Fe2N-N-doped graphitic nanocarbons composite (Fe2N-NGC)46.


Porous VO(x)N(y) nanoribbons supported on CNTs as efficient and stable non-noble electrocatalysts for the oxygen reduction reaction.

Huang K, Bi K, Lu YK, Zhang R, Liu J, Wang WJ, Tang HL, Wang YG, Lei M - Sci Rep (2015)

ORR activities of different VOxNy-based catalysts compared with Pt/C catalyst at 1600 rpm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663630&req=5

f5: ORR activities of different VOxNy-based catalysts compared with Pt/C catalyst at 1600 rpm.
Mentions: The ORR performances of VOxNy and VOxNy-CNTs catalysts with VOxNy-XC 72R and commercial Pt/C as the references have been further investigated in alkaline electrolyte. As shown in Fig. 5, the ORR polarization curves for all kinds of catalysts at 1600 rpm in O2-saturated 0.1 M KOH exhibit a combined kinetic-diffusion control of charge transfer and mass transport process at different potentials. It is obvious that the support of carbon can improve the onset potential, half-wave potential and the diffusion-limited current density of pure VOxNy nanoribbons catalyst, and the hybrid with CNTs displays the strongest competitiveness with respect to the commercial Pt/C. Although the onset potential (0.88 V Vs. RHE) and half-wave potential (0.77 V Vs. RHE) of VOxNy-CNTs are 0.10 and 0.07 V smaller than those of Pt/C electrode, the diffusion-limited current density is about 0.4 mA/cm2 larger. Meanwhile, the stabilities of VOxNy-based electrodes are quite superior to that of Pt/C electrode no matter whether adding 3M Methanol at 500 s. As shown in the inset of Fig. 6, the current densities of pure VOxNy electrode, VOxNy-Xc 72R electrode, VOxNy-CNTs electrode and Pt/C electrode remain 98.73%, 89.76%, 93.68% and 82.95% after 1000 s compared with the initial ones. The increased loss with the addition of XC 72R and CNTs can be attributed to the oxidation of carbon under dynamic potential conditions and high-oxygen environment3940. Furthermore, unlike the instantaneous current density jump for Pt/C electrode due to the addition and the following electro-oxidation of methanol41, all VOxNy-based electrodes exhibit superior methanol tolerance with negligible changes. In addition, the ORR performance in alkaline electrolyte of VOxNy-CNTs is also highly comparable to other widely studied non-precious electrocatalysts, such as 3D nitrogen-doped graphene aerogel-supported Fe3O4 nanoparticles (Fe3O4/N-GAs)42, carbon nanotubes supported MnOx hybrids (MnOx/CNTs)43, carbon-supported CoSe2 nanocatalyst (CoSe2/C)44, cobalt and nitrogen-cofunctionalized graphene (Co-N-GN)45 and Fe2N-N-doped graphitic nanocarbons composite (Fe2N-NGC)46.

Bottom Line: Novel nanocomposites of carbon nanotubes supported porous VO(x)N(y) nonoribbons (VO(x)N(y)-CNTs) have been synthesized by the annealing of the sol-gel mixture of CNTs and V2O5 under NH3 atmosphere as well as the ageing process in air.Besides the morphological and structural characterizations revealed by TEM, SEAD, EDS, XRD and XPS measurements, typical electrochemical tests including cyclic voltammetry (CV), rotating disk electrode (RDE) and chronoamperometry have been employed to determine the oxygen reduction reaction (ORR) performance of VO(x)N(y)-CNTs.Therefore, we have reasonable grounds to believe that this new VO(x)N(y)-CNTs nanocomposites can be regarded as a promising non-precious methanol-tolerant ORR catalyst candidate for alkaline fuel cells.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Information Photonics and Optical Communications &School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China.

ABSTRACT
Novel nanocomposites of carbon nanotubes supported porous VO(x)N(y) nonoribbons (VO(x)N(y)-CNTs) have been synthesized by the annealing of the sol-gel mixture of CNTs and V2O5 under NH3 atmosphere as well as the ageing process in air. Besides the morphological and structural characterizations revealed by TEM, SEAD, EDS, XRD and XPS measurements, typical electrochemical tests including cyclic voltammetry (CV), rotating disk electrode (RDE) and chronoamperometry have been employed to determine the oxygen reduction reaction (ORR) performance of VO(x)N(y)-CNTs. Inspiringly, the results indicate that VO(x)N(y)-CNTs catalyst exhibits a 0.4 mA/cm(2) larger diffusion-limited current density, a 0.10  V smaller onset potential value, a 10.73% less of ORR current decay and an excellent methanol-tolerance compared with commercial Pt/C catalyst. Therefore, we have reasonable grounds to believe that this new VO(x)N(y)-CNTs nanocomposites can be regarded as a promising non-precious methanol-tolerant ORR catalyst candidate for alkaline fuel cells.

No MeSH data available.


Related in: MedlinePlus