Engineered Carbons Supports (ECSs) for Cathode Oxygen Reduction Reaction Electrocatalysts

Thursday, 5 October 2017: 08:20
National Harbor 2 (Gaylord National Resort and Convention Center)
A. Serov, A. Lubers, G. McCool (Pajarito Powder, LLC), S. McKinney (Pajarito Powdeer, LLC), H. Romero (Pajarito Powder, LLC), and B. Zulevi (Pajarito Powder LLC)
In the development of PEMFC fuel cells main attention is mainly devoted to the "active" portion of the catalysts system, the precious metal nanoparticles. While this approach has led to great improvement in specific activity, existing catalysts are still not meeting the combination of performance and cost necessary for the commercialization of PEMFC.

A key limitation to catalysts today arises from reliance on carbon blacks (CBs) supports that is a matrix for the precious metal catalyst nanoparticles, but which corrode under certain operating conditions. Carbon support modifications that rely on "top-down" graphitization of CB's have so far improved resistance to carbon corrosion, but at the cost of reduced stabilization of precious metal dissolution.

Pajarito Powder developed a "bottom-up" approach where Engineered Carbon Supports (ECSs) are made from organic precursors that yield highly graphitic materials with controllable morphology and increased resistance to corrosion. This method which is based on technologies licensed from the University of New Mexico [1,2], Northeastern University, and Los Alamos National Laboratory allows manufacture of carbonaceous powders with controllable level of graphitization with reasonably high yields. The final chemical structure (doping with heteroatoms), morphology (pore size and modality) and surface area can be precisely controlled by selection of organic molecules and types of sacrificial supports.

Pt/C catalysts made using these Engineered Carbon Supports maintain performance under carbon corrosion test protocols and thus demonstrate their utility in achieving the performance/price balance needed for commercializing PEMFCs. The catalyst characteristics and performance, as well as economics of this approach will be presented and discussed. In addition, preliminary results in synthesis and performance testing of hybrid catalysts made using platinum group metal -free (PGM-free) oxygen reduction reaction (ORR) catalysts made using the VariPore platform with and without Pt nanoparticles added will be presented.

[1] S. Stariha, K. Artyushkova, M. J. Workman, A. Serov, S. McKinney, B. Halevi, P. Atanassov "PGM-free Fe-N-C catalysts for oxygen reduction reaction: Catalyst layer design" J. Power Sources 326 (2016) 43–49.

[2] A. Serov, M. J. Workman, K. Artyushkova, P. Atanassov, G. McCool, S. McKinney, H. Romero, B. Halevi, T. Stephenson "Highly stable precious metal-free cathode catalyst for fuel cell application", J. Power Sources 327 (2016) 557-564.