Oxygen reduction activity and methanol tolerance of carbon-supported PtV nanoparticles and the effects of heat treatment at low temperatures

Abstract

This paper reports on oxygen reduction activity and methanol tolerance of PtV/C prepared by a polyol method and the effects of heat treatments in reducing environments at low temperatures (up to 300°C). The as-prepared catalyst showed a low content of alloyed vanadium, but it was considerably more active for the oxygen reduction reaction than Pt/C and had superior methanol tolerance. Dispersive X-ray absorption spectroscopy measurements around the Pt L 3 edge indicated that the presence of vanadium in the catalyst increased the Pt 5d-band vacancy at the time that it seems to diminish the Pt coverage by adsorbed OH species. Heat treatments at 150, 200, and 300°C carried out in strongly reducing conditions produced minor changes in the degree of alloying together with a moderate particle growth. The largest incorporation of vanadium in the alloyed phase was observed after heating at 150°C while a decrease in the alloying and Pt segregation to the surface were observed for higher treatment temperatures. In general, heat treatments were detrimental for oxygen reduction activity, suggesting that the presence of vanadium oxides might play a role. In addition, the decreased in methanol tolerance might be associated to Pt segregation to the surface.

A novel electrochemical cell for operando X-ray absorption measurements at low energies: Probing electrochemically induced electronic changes in palladium

“…It is interesting to note that similar behavior, i.e., increasing intensity of the X-ray absorption peak for more positive applied potential, has been reported for Pt and Pt-based carbon-supported materials [24][25][26]. That change in electronic properties was attributed to the effect of oxygenated species leading to a higher electronic vacancy of the 5d band [9].…”

Polyaniline structure on common carbon supports to improve the performance of low-platinum-based ORR electrocatalysts

“…[16,17], forming alloys with other transition metals (Fe, Co, Ni, Cr, V, etc.) [18][19][20][21][22], seeking more durable supports (graphene, carbon nano tubes, carbon aerogels, tungsten carbide, titanium dioxide, ceria), etc [23][24][25][26][27][28][29][30][31]. The general method of alloy formation with other transition metals deactivates the catalyst due to the loss and agglomeration of platinum caused by the dissolution of the transition metal [6,32].Stable core-shell structure was di cult to be formed in scale-up preparation, and the cost would be high and not suitable for next industrial application [33,34].…”

Highly effective bi‐functional electrochemical activity of Ag 2 O‐PrO 2 / γ‐Al 2 O 3 electrocatalysts towards OER and ORR

“…To get efficacious and reasonably priced energy conversion from FCs, their performance must be improved. In this framework, there is need of competent catalyst for electrode material to overwhelm the over‐potential losses associated with poor kinetics of ORR, HER, and OER 9‐11 . The electro‐catalyst must have a low over potential and a potential working close to Nernstian‐potential 12 .…”

“…In this framework, there is need of competent catalyst for electrode material to overwhelm the over-potential losses associated with poor kinetics of ORR, HER, and OER. [9][10][11] The electro-catalyst must have a low over potential and a potential working close to Nernstian-potential. 12 Presently, Platinum (Pt) based materials proved to be active catalysts towards HER and ORR, 10,13,14 while Iridium (Ir) based materials have been well-known catalysts for OER.…”