Structure and Activity of Novel Pt Core-Shell Catalysts for the Oxygen Reduction Reaction

Recent performance and cost studies predict that the high PGM loadings in the electrodes of today's direct hydrogen fuel cells will prove a limiting factor in their commercial viability for automotive applications. Significant breakthroughs in electrocatalyst technology yielding materials with high activity, low cost and good durability are required. This paper reports on a collaborative effort which has focussed on the exciting core-shell oxygen reduction catalysts pioneered by Brookhaven National Laboratory. These materials promise high catalyst activity and PGM thrifting although to date, are typically fabricated by in-situ electrochemical techniques. Following the development of scalable syntheses, extensive catalyst characterisation methods have been employed to analyse and verify the success of a scaled Pt-ML/Pd3Co/C catalyst. Although synthetic challenges remain, the scaled core-shell materials yield RDE activities of 0.72 A/mg(Pt) constituting an impressive 3.7x improvement in Pt activity relative to Pt/C and exceeding the 0.44 A/mg(Pt) automotive target.