Highly stable and active PEM-FC cathode catalyst with a protective Nitride coating

תמונה_סמינרים
31.05.2020
14:30
Seminar by Zoom
Mr. Mordechai Kattan, M.Sc. Candidate

Mr. Mordechai Kattan, M.Sc. Candidate

Faculty of Materials Science and Engineering
Technion – Israel Institute of Technology
Haifa 3200003, Israel

A common Fuel Cell (FC) catalyst comprised of nano-sized Pt- or Pt-alloy clusters attached to a high area carbon support. The accepted catalyst degradation mechanism suggests that catalytic activity decay takes place because of a decrease in the ECSA (electrochemically active surface area) of the catalyst-active precious metal clusters. There are two main parallel channels of such ECSA decay: (1) a migration of the precious metal clusters across the carbon support surface, followed by clusters coalescence, and (2) a detachment of precious metal clusters from the carbon support. It is suggest the oxidation of the carbon material adjacent to the precious metal catalyst clusters. One of the ways to prevent the carbon corrosion is to coat the carbon support with a corrosion-proof layer. The coating should leave the catalyst centers accessible for reagents, and the coating should also be electronically conductive. Needless to say, the coating should be corrosion-proof under the FC conditions.

In this study, we report on coating the carbon substrate with a thin titanium nitride (TiN) layer, via the application of an atomic layer deposition (ALD) technique. The Pt-clusters should be left free from the coating, thought; for this end, the clusters are to be protected with a screening material, which is absorbed only onto the platinum, protecting it from TiN plating. The protective material should be stable under the ALD conditions and, at the same time, it should be easily removable after the ALD processing is over, without compromising the catalyst integrity and activity.

Supervisor: Prof. Yair Ein-Eli

Seminar by Zoom: Click here