Limits...
Novel VN/C nanocomposites as methanol-tolerant oxygen reduction electrocatalyst in alkaline electrolyte.

Huang K, Bi K, Liang C, Lin S, Zhang R, Wang WJ, Tang HL, Lei M - Sci Rep (2015)

Bottom Line: A novel VN/C nanostructure consisting of VN nanoparticles and graphite-dominant carbon layers is synthesized by nitridation of V2O5 using melamine as reductant under inert atmosphere.Moreover, the electrocatalytic performance of VN/C towards oxygen reduction reaction (ORR) in alkaline electrolyte is fascinating.The results show that VN/C has a considerable ORR activity, including a 75 percent value of the diffusion-limited current density and a 0.11 V smaller value about the onset potential with respect to Pt/C catalyst.

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
A novel VN/C nanostructure consisting of VN nanoparticles and graphite-dominant carbon layers is synthesized by nitridation of V2O5 using melamine as reductant under inert atmosphere. High crystalline VN nanoparticles are observed to be uniformly distributed in carbon layers with an average size of ca13.45 nm. Moreover, the electrocatalytic performance of VN/C towards oxygen reduction reaction (ORR) in alkaline electrolyte is fascinating. The results show that VN/C has a considerable ORR activity, including a 75 percent value of the diffusion-limited current density and a 0.11 V smaller value about the onset potential with respect to Pt/C catalyst. Moreover, the excellent methanol-tolerance performance of VN/C has also been verified with 3 M methanol. Combined with the competitive prices, this VN/C nanocomposite can serve as an appropriate non-precious methanol-tolerant ORR catalyst for alkaline fuel cells.

No MeSH data available.


Related in: MedlinePlus

Koutechy-Levich (K-L) plots (A) at different electrode potentials for VN/C and Tafel slope (B) of VN/C derived by the mass-transport correction of RDE data at 1600 rpm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4477409&req=5

f5: Koutechy-Levich (K-L) plots (A) at different electrode potentials for VN/C and Tafel slope (B) of VN/C derived by the mass-transport correction of RDE data at 1600 rpm.

Mentions: It is well known to all that there are two major pathways for the reduction of oxygen in alkaline aqueous solution: direct 4-electron pathway to “hydroxyl ion” and 2-electron pathway with “peroxide” as the reduction product. According to Koutechy-Levich theory, the electron transfer number in ORR can be calculated using equations as follows:where J and JK are the measured and kinetic-limiting current densities, ω is the rotation speed (rpm), n is the transferred electron number, F is the Faraday constant (F = 96485 C mol−1), C is the concentration of O2 in 0.1 M KOH solution (C = 1.2 × 10−6 mol cm−3), D is the diffusion coefficient of O2 (D = 1.9 × 10−5 cm2 s−1), V is the kinematic viscosity (V = 0.01 cm2 s−1) referring to the previous reports3738. Based on the Rotating-disk voltammograms of VN/C electrode in O2-saturated 0.1 M KOH solution from 400 to 2000 rpm in Fig. 4A, the average number of electrons transferred per oxygen molecule involved in VN/C catalyst for ORR is 3.95 which suggests a direct 4-electron reduction process (Fig. 5A). Moreover, on the basis of Tafel equations:


Novel VN/C nanocomposites as methanol-tolerant oxygen reduction electrocatalyst in alkaline electrolyte.

Huang K, Bi K, Liang C, Lin S, Zhang R, Wang WJ, Tang HL, Lei M - Sci Rep (2015)

Koutechy-Levich (K-L) plots (A) at different electrode potentials for VN/C and Tafel slope (B) of VN/C derived by the mass-transport correction of RDE data at 1600 rpm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4477409&req=5

f5: Koutechy-Levich (K-L) plots (A) at different electrode potentials for VN/C and Tafel slope (B) of VN/C derived by the mass-transport correction of RDE data at 1600 rpm.
Mentions: It is well known to all that there are two major pathways for the reduction of oxygen in alkaline aqueous solution: direct 4-electron pathway to “hydroxyl ion” and 2-electron pathway with “peroxide” as the reduction product. According to Koutechy-Levich theory, the electron transfer number in ORR can be calculated using equations as follows:where J and JK are the measured and kinetic-limiting current densities, ω is the rotation speed (rpm), n is the transferred electron number, F is the Faraday constant (F = 96485 C mol−1), C is the concentration of O2 in 0.1 M KOH solution (C = 1.2 × 10−6 mol cm−3), D is the diffusion coefficient of O2 (D = 1.9 × 10−5 cm2 s−1), V is the kinematic viscosity (V = 0.01 cm2 s−1) referring to the previous reports3738. Based on the Rotating-disk voltammograms of VN/C electrode in O2-saturated 0.1 M KOH solution from 400 to 2000 rpm in Fig. 4A, the average number of electrons transferred per oxygen molecule involved in VN/C catalyst for ORR is 3.95 which suggests a direct 4-electron reduction process (Fig. 5A). Moreover, on the basis of Tafel equations:

Bottom Line: A novel VN/C nanostructure consisting of VN nanoparticles and graphite-dominant carbon layers is synthesized by nitridation of V2O5 using melamine as reductant under inert atmosphere.Moreover, the electrocatalytic performance of VN/C towards oxygen reduction reaction (ORR) in alkaline electrolyte is fascinating.The results show that VN/C has a considerable ORR activity, including a 75 percent value of the diffusion-limited current density and a 0.11 V smaller value about the onset potential with respect to Pt/C catalyst.

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
A novel VN/C nanostructure consisting of VN nanoparticles and graphite-dominant carbon layers is synthesized by nitridation of V2O5 using melamine as reductant under inert atmosphere. High crystalline VN nanoparticles are observed to be uniformly distributed in carbon layers with an average size of ca13.45 nm. Moreover, the electrocatalytic performance of VN/C towards oxygen reduction reaction (ORR) in alkaline electrolyte is fascinating. The results show that VN/C has a considerable ORR activity, including a 75 percent value of the diffusion-limited current density and a 0.11 V smaller value about the onset potential with respect to Pt/C catalyst. Moreover, the excellent methanol-tolerance performance of VN/C has also been verified with 3 M methanol. Combined with the competitive prices, this VN/C nanocomposite can serve as an appropriate non-precious methanol-tolerant ORR catalyst for alkaline fuel cells.

No MeSH data available.


Related in: MedlinePlus