Limits...
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

XPS spectra of VOxNy and VOxNy-CNTs: survey (A), O 1 s and V 2P (B), N 1S (C) and C 1S (D).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4663630&req=5

f4: XPS spectra of VOxNy and VOxNy-CNTs: survey (A), O 1 s and V 2P (B), N 1S (C) and C 1S (D).

Mentions: XPS analysis in Fig. 4 further reveals that the components of VOxNy and VOxNy-CNTs are consist of V, N, O, and C elements from the survey spectra. Compared with the high intensity peak of CNTs in VOxNy-CNTs nanocomposites, it is notable that the signal of C 1S peak for pure VOxNy nanoribbons can be attributed to the air contamination on surface28, which exhibits a symmetric peak at 284.8 eV (Fig. 4D). Figure 4B shows the high-resolution XPS spectra of O 1 s and V 2p, where two peaks at 514.2 V (2p 3/2) and 521.5 eV (2p 1/2) can be ascribed to vanadium atoms in the VN crystalline, other four vanadium-based peaks at 515.7, 517.3, 523.4 and 525.1 eV are belong to vanadium oxides and the peaks at 532.2 and 530.3 eV of O 1s can be attributed to lattice oxygen in VxOy due to the ageing process in air and surface adsorbed hydroxyl oxygen, respectively2930313233. In addition, it is found that the chemical states of N and C elements for VOxNy-CNTs are quite different from pure VOxNy nanoribbons as shown in Fig. 4C,D. The peak of N 1s spectra at 397.5 eV can be assigned to the corresponding metal nitrides while the other two peaks at 399.5 and 401.3 eV are belonging to pyrrolic and quaternary-graphitic separately31. The C 1S spectrum also exhibits a typical aromatic C-N coordination in a graphitic carbon nitride framework at 288.2 eV except for the non-oxygenated ring C (284.8 eV, C-C, C = C) as well as the C-O bond at 286.3 eV3435. These results indicate that a surface modification and N-doping of CNTs happened sequentially during the acid treatment and annealing process, which have been proved to show excellent ORR activity363738.


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)

XPS spectra of VOxNy and VOxNy-CNTs: survey (A), O 1 s and V 2P (B), N 1S (C) and C 1S (D).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f4: XPS spectra of VOxNy and VOxNy-CNTs: survey (A), O 1 s and V 2P (B), N 1S (C) and C 1S (D).
Mentions: XPS analysis in Fig. 4 further reveals that the components of VOxNy and VOxNy-CNTs are consist of V, N, O, and C elements from the survey spectra. Compared with the high intensity peak of CNTs in VOxNy-CNTs nanocomposites, it is notable that the signal of C 1S peak for pure VOxNy nanoribbons can be attributed to the air contamination on surface28, which exhibits a symmetric peak at 284.8 eV (Fig. 4D). Figure 4B shows the high-resolution XPS spectra of O 1 s and V 2p, where two peaks at 514.2 V (2p 3/2) and 521.5 eV (2p 1/2) can be ascribed to vanadium atoms in the VN crystalline, other four vanadium-based peaks at 515.7, 517.3, 523.4 and 525.1 eV are belong to vanadium oxides and the peaks at 532.2 and 530.3 eV of O 1s can be attributed to lattice oxygen in VxOy due to the ageing process in air and surface adsorbed hydroxyl oxygen, respectively2930313233. In addition, it is found that the chemical states of N and C elements for VOxNy-CNTs are quite different from pure VOxNy nanoribbons as shown in Fig. 4C,D. The peak of N 1s spectra at 397.5 eV can be assigned to the corresponding metal nitrides while the other two peaks at 399.5 and 401.3 eV are belonging to pyrrolic and quaternary-graphitic separately31. The C 1S spectrum also exhibits a typical aromatic C-N coordination in a graphitic carbon nitride framework at 288.2 eV except for the non-oxygenated ring C (284.8 eV, C-C, C = C) as well as the C-O bond at 286.3 eV3435. These results indicate that a surface modification and N-doping of CNTs happened sequentially during the acid treatment and annealing process, which have been proved to show excellent ORR activity363738.

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