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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

CV curves of VOxNy (A), VOxNy-XC 72R (B) and VOxNy-CNTs (C) as ORR catalysts in N2/O2-saturated 0.1 M KOH solution.
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f7: CV curves of VOxNy (A), VOxNy-XC 72R (B) and VOxNy-CNTs (C) as ORR catalysts in N2/O2-saturated 0.1 M KOH solution.

Mentions: To further understand the enhanced performance of VOxNy-CNTs catalysts with respect to VOxNy-XC 72R and pure VOxNy electrodes, cyclic voltammetry (CV) curves under both N2- and O2-saturated 0.1 M KOH electrolyte have been also recorded in Fig. 7. As can be seen, there are no obvious oxidation or reduction current peaks in all CV curves under N2-saturated KOH solution differing from Fe-N/C catalysts which present redox couples due to the existence of instable metal ions47. Thus, this result also indicates the high electrochemical stability of VOxNy over the whole measured potential range. Meanwhile, significant ORR peaks can be observed for VOxNy-XC 72R (0.65 V vs. RHE) and VOxNy-CNTs (0.75 V vs. RHE) electrodes under the O2-saturated condition compared with pure VOxNy electrode, which suggests the decreased overpotential and favorable charge transfer process for ORR4849. Considering the above results of ORR polarization curves and chronoamperometric responses, VOxNy-CNTs composites exhibit a fascinating ORR activity and stability. As is well-known to all, ORR is a surface chemical process where the consumption of oxygen occurs on the surface of electrode materials. Therefore, the enhanced performance of VOxNy-CNTs composites is believed to be closely related to the surface chemical states: (i) the bond between the carbon and the nitrogen is favorable to elevate the ORR electro-catalytic activity; (ii) the surface VOxNy layer itself benefits the stability and tolerance of methanol.


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)

CV curves of VOxNy (A), VOxNy-XC 72R (B) and VOxNy-CNTs (C) as ORR catalysts in N2/O2-saturated 0.1 M KOH solution.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f7: CV curves of VOxNy (A), VOxNy-XC 72R (B) and VOxNy-CNTs (C) as ORR catalysts in N2/O2-saturated 0.1 M KOH solution.
Mentions: To further understand the enhanced performance of VOxNy-CNTs catalysts with respect to VOxNy-XC 72R and pure VOxNy electrodes, cyclic voltammetry (CV) curves under both N2- and O2-saturated 0.1 M KOH electrolyte have been also recorded in Fig. 7. As can be seen, there are no obvious oxidation or reduction current peaks in all CV curves under N2-saturated KOH solution differing from Fe-N/C catalysts which present redox couples due to the existence of instable metal ions47. Thus, this result also indicates the high electrochemical stability of VOxNy over the whole measured potential range. Meanwhile, significant ORR peaks can be observed for VOxNy-XC 72R (0.65 V vs. RHE) and VOxNy-CNTs (0.75 V vs. RHE) electrodes under the O2-saturated condition compared with pure VOxNy electrode, which suggests the decreased overpotential and favorable charge transfer process for ORR4849. Considering the above results of ORR polarization curves and chronoamperometric responses, VOxNy-CNTs composites exhibit a fascinating ORR activity and stability. As is well-known to all, ORR is a surface chemical process where the consumption of oxygen occurs on the surface of electrode materials. Therefore, the enhanced performance of VOxNy-CNTs composites is believed to be closely related to the surface chemical states: (i) the bond between the carbon and the nitrogen is favorable to elevate the ORR electro-catalytic activity; (ii) the surface VOxNy layer itself benefits the stability and tolerance of methanol.

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