New publications on nanostructured catalysts

The effort of our group to reduce the costs of water electrolyzers and hydrogen fuel cells is reflected in two new articles, published respectively in the International Journal of Hydrogen Energy and in the Journal of Power Sources. Both studies deal with thin-film catalysts deposited by magnetron sputtering, and both show how the content of precious metals in anode catalysts can be reduced, but the two approaches differ.

The first article, titled "Magnetron sputtered thin-film vertically segmented Pt-Ir catalyst supported on TiC for anode side of proton exchange membrane unitized regenerative fuel cells", presents the work of Dr. Peter Kúš and co-workers on anode catalysts for PEM-URFCs. A unitized regenerative fuel cell (URFC) is a device that can act both as a fuel cell and as an electrolyzer. In hydrogen energy-storage facilities, the use of one device (URFC) instead of two devices (electrolyzer and fuel cell) may obviously reduce the amount of catalysts used, besides simplifying the facility design. A sandwich-like Ir/TiC/Pt catalyst, deposited by magnetron sputtering on the proton-exchange membrane (PEM) in the URFC, performs nearly as well as conventional single-purpose catalysts in electrolyzers and fuel cells, while containing less than half the amount of the precious metals. The results were partly presented already in Peter's dissertation and were well recognized.

The other article is named "Highly developed nanostructuring of polymer-electrolyte membrane supported catalysts for hydrogen fuel cell application" and authored by Dr. Yurii Yakovlev and co-workers. This study deals only with hydrogen fuel cells (not URFCs) but goes much farther in the reduction of the precious metal content. By magnetron sputtering of CeO₂ onto a PEM in an Ar + O₂ atmosphere, the membrane gets not only covered with CeO₂ but also partly etched. The result is a rugged nanostructure of high surface area on the membrane. Subsequent deposition of a tiny amount of platinum (21 μg/cm²) produces nearly as efficient a catalyst as a commercial platinum one.