SiC nanocrystals as Pt catalyst supports for fuel cell applications

Abstract

A robust catalyst support is pivotal to Proton Exchange Membrane Fuel Cells (PEMFCs) to overcome challenges such as catalyst support corrosion, low catalyst utilization and overall capital cost. SiC is a promising candidate material which could be applied as a catalyst support in PEMFCs. SiC nanocrystals are here synthesized using nano-porous carbon black (Vulcan Ò XC-72) as a template using two different reactions, which result in particle sizes in the ranges of 50-150 nm (SiC-SPR) and 25-35 nm (SiC-NS). Pt nano-catalysts of size 5-8 nm and 4-5 nm have successfully been uniformly deposited on the nanocrystals of SiC-SPR and SiC-NS by the polyol method. The SiC substrates are subjected to an acid treatment to introduce the surface groups, which help to anchor the Pt nano-catalysts. These SiC based catalysts have been found to have a higher electrochemical activity than commercially available Vulcan based catalysts (BASF & HISPEC). These promising results signal a new era of SiC based catalysts for fuel cell applications.

Enhancement of high temperature PEMFC stability using catalysts based on Pt supported on SiC based materials

“…We must bear in mind that the GDL and the PBI are commercials, so the differences among the different MEAs are in the catalyst layers because of the use of catalyst with different supports and hence different properties. Although, Pt/SiC has been studied recently in literature [5,13], most of the results shown are in half cells and not fuel cell results in H 2 /Air or O 2 PEMFC have been found by the authors to compare our results with. Finally, the charge transfer resistance (R ct ) explains the best stability of the MEA with Pt/SiCTiC and the lower performance with respect to the MEA with the commercial catalyst Pt/C, because of the lowest variation with time and the higher values of the R ct , respectively.…”

“…Surface area, porosity, electrical conductivity, electrochemical stability and surface functional groups characterise a support [3]. It is also well known that the conventional used carbon support materials are susceptible to oxidation under the chemical and electrochemical conditions at both electrodes in the fuel cell [3][4][5]. Thus, new materials based on advanced carbonaceous and non-carbonaceous materials (oxides, carbides.…”

“…Different authors have tested previously SiC based materials [5,13] for electrodes in low temperature PEMFC or Nafion-based PEMFC but never for PBI based HT-PEMFCs as authors knowledge. Only one previous work by our group shows preliminary results with SiC but in the microporous layer of the electrode for HT-PEMFC but not as catalyst support [14].…”

Electrochemical Stability and Postmortem Studies of Pt/SiC Catalysts for Polymer Electrolyte Membrane Fuel Cells

“…This has been proved useful for other carbides, such as tungsten carbide (WC), where above 0.8 V RHE the WC transforms into at least two WO x species leading to significant Pt detachment 23 . 4 In our previous work, we reported on a synthesis method of Pt/SiC, in which the addition of carbon is not necessary 24 . The electrochemical activity values for methanol oxidation and oxygen reduction reactions were similar to those obtained for Pt/C 25 .…”

Development of stable electrochemical catalysts using ordered mesoporous carbon/silicon carbide nanocomposites

“…Among these alternative supports, silicon carbide (SiC) materials have been proposed to be of interest due to their hardness, chemical inertness and high thermal stability up to 1200 C in an oxidative environment [27e32]. Dhiman et al attempted to prepare a Pt catalyst supported on SiC nanocrystals that were obtained from a reaction of SiO 2 vapors with carbon black at 1450 C [29]. The electrochemical measurements indicated that the ECSA of the Pt/SiC catalyst was larger than that of a commercial Pt/C catalyst (20 wt% Pt, E-TEK).…”