An ion exchange route to produce carbon supported nanoscale vanadium carbide for electrocatalysis

Abstract

We demonstrate that vanadium carbide nanocrystals down to 2 nm on carbon (C-VC x ) can be synthesized through a novel route based on an ionic exchange process to locally anchor the species of interest by design. The structures, morphologies and catalytic performance of the as-synthesized nanomaterials were characterized by various physical and electrochemical methods. The results indicate that electrocatalysts made with Pt nanoparticles on C-VC x (Pt/C-VC x ) are highly active and stable for both the oxygen reduction reaction (ORR) and methanol oxidation. A mass activity of 267.1 mA mg À1 Pt at 0.9 V was obtained for the oxygen reduction reaction, which is much higher than that of a commercial Pt/C electrocatalyst (112.5 mA mg À1 Pt ). It was also demonstrated that the onset potential for methanol oxidation on Pt/C-VC x is negatively shifted by more than 100 mV compared with that on Pt/C. The origin of these improvements in the catalytic activity can be attributed to the synergistic effect between Pt and VC x . The novelty of the present method is its simplicity and effectiveness, and it can be readily scaled up for mass production of other nanomaterials.

Nitrogen-doped graphene–vanadium carbide hybrids as a high-performance oxygen reduction reaction electrocatalyst support in alkaline media

“…The resulting hybrid nanocatalyst shows better catalytic performance than commercial Pt/C (Pt 10 wt%) for ORR in alkaline solutions in terms of half-wave potential and mass activity. The hybrid nanocatalyst also shows superior or similar performance compared with Pt-VC 27,30 and N-doped graphene 23,31,34 catalysts reported so far.…”

“…24,25 The use of transition-metal carbides as the Pt support has been reported to have a promotional effect over traditional carbon-based supports in terms of mass activity and stability. 18,[26][27][28][29][30] However, preparing nano-sized metal carbides is a challenge and due to the relatively low specic surface area, the catalytic activity of the resulting Pt/ metal carbide catalysts is yet to be improved. 27,30 On the other hand, nitrogen (N)-doped graphene/reduced graphene oxide (RGO) has been demonstrated to exhibit great catalytic performance for ORR due to its high electrical conductivity, large specic surface area, and the presence of nitrogen doping and rich defects.…”

“…18,[26][27][28][29][30] However, preparing nano-sized metal carbides is a challenge and due to the relatively low specic surface area, the catalytic activity of the resulting Pt/ metal carbide catalysts is yet to be improved. 27,30 On the other hand, nitrogen (N)-doped graphene/reduced graphene oxide (RGO) has been demonstrated to exhibit great catalytic performance for ORR due to its high electrical conductivity, large specic surface area, and the presence of nitrogen doping and rich defects. 21,23,31 Therefore, nanohybrids composed of metal carbide nanocrystals distributed on the surface of N-doped graphene are anticipated to be an attractive support for Pt as an ORR catalyst.…”

MoO2 nanocrystals down to 5 nm as Pt electrocatalyst promoter for stable oxygen reduction reaction

“…However, although the above metal oxides could be easily synthesized, most of the particles are too big to fully exert the promotion effect on noble metal electrocatalysts [39,40]. Moreover, most of the metal oxides actually have not good electrochemical stabilities.…”

Angstrom-scale vanadium carbide rods as Pt electrocatalyst support for efficient methanol oxidation reaction

“…However, the traditional synthesis methods of vanadium carbide (and also other carbides) lead to large particle sizes that are tens or hundreds of nanometers in diameter. [32][33][34][35] have been reported, great promotion effects of V 8 C 7 on activities of Pt or Pd have been found. [32][33][34][35] have been reported, great promotion effects of V 8 C 7 on activities of Pt or Pd have been found.…”