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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

TEM image (A) and element mapping spectra about C (B), V (C), O (D) and N (E) of VOxNy-CNTs.
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f2: TEM image (A) and element mapping spectra about C (B), V (C), O (D) and N (E) of VOxNy-CNTs.

Mentions: Figure 1 shows the morphological characters of as-prepared samples by transmission electron microscope (TEM) equipped with the selected area electron diffraction (SAED). It can be seen that there are plentiful pores distributing in the VOxNy nanoribbons due to the topotactic transformation whether supported by CNTs or not (Fig. 1A,D). The high-resolution TEM images show clear lattice fringes with an interfringe spacing of 0.203 nm which corresponds to the d-spacing of (200) planes (Fig. 1C). As for VOxNy-CNTs composites, VOxNy nanoribbons with a few tens of nanometers in widths and lengths up to micrometer range are randomly supported by plentiful tortuous CNTs (which are more transparent to the electron beam). Moreover, the element mapping spectra visually displayed in Fig. 2 demonstrate the locations of VOxNy nanoribbons in the composites. Figure 2B shows the C element from CNTs supporter which distributes everywhere and randomly, while the distributions of V, O and N elements are in accordance with the VOxNy nanoribbons to a great extent and the messy existence of O and N elements in Fig. 2C,D is believed to come from the surface species of CNTs. As the XRD patterns shown in Fig. 3, five main peaks ranging from 35° to 85° for both VOxNy and VOxNy-CNTs can match well with (111), (200), (220), (311) and (222) planes of the typical stoichiometric face-centered (fcc) VO (JCPDS No. 75-0048) or VN (JCPDS No. 73–0528) structures, where the figure of merit (FOM) values are 1.2 and 5.6 respectively. This result can be ascribed to the penetration of oxygen atoms into the VN crystal lattice17, which happened once the prepared samples were taken off from the furnace. Moreover, the broad peak for VOxNy-CNTs sample appears at about 26° which corresponds to the (002) plane of graphite carbon (JCPDS No. 75–1261) and confirms the existence of CNTs.


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)

TEM image (A) and element mapping spectra about C (B), V (C), O (D) and N (E) of VOxNy-CNTs.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: TEM image (A) and element mapping spectra about C (B), V (C), O (D) and N (E) of VOxNy-CNTs.
Mentions: Figure 1 shows the morphological characters of as-prepared samples by transmission electron microscope (TEM) equipped with the selected area electron diffraction (SAED). It can be seen that there are plentiful pores distributing in the VOxNy nanoribbons due to the topotactic transformation whether supported by CNTs or not (Fig. 1A,D). The high-resolution TEM images show clear lattice fringes with an interfringe spacing of 0.203 nm which corresponds to the d-spacing of (200) planes (Fig. 1C). As for VOxNy-CNTs composites, VOxNy nanoribbons with a few tens of nanometers in widths and lengths up to micrometer range are randomly supported by plentiful tortuous CNTs (which are more transparent to the electron beam). Moreover, the element mapping spectra visually displayed in Fig. 2 demonstrate the locations of VOxNy nanoribbons in the composites. Figure 2B shows the C element from CNTs supporter which distributes everywhere and randomly, while the distributions of V, O and N elements are in accordance with the VOxNy nanoribbons to a great extent and the messy existence of O and N elements in Fig. 2C,D is believed to come from the surface species of CNTs. As the XRD patterns shown in Fig. 3, five main peaks ranging from 35° to 85° for both VOxNy and VOxNy-CNTs can match well with (111), (200), (220), (311) and (222) planes of the typical stoichiometric face-centered (fcc) VO (JCPDS No. 75-0048) or VN (JCPDS No. 73–0528) structures, where the figure of merit (FOM) values are 1.2 and 5.6 respectively. This result can be ascribed to the penetration of oxygen atoms into the VN crystal lattice17, which happened once the prepared samples were taken off from the furnace. Moreover, the broad peak for VOxNy-CNTs sample appears at about 26° which corresponds to the (002) plane of graphite carbon (JCPDS No. 75–1261) and confirms the existence of CNTs.

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