High-Performance Osmium Nanoparticle Electrocatalyst for Direct Borohydride PEM Fuel Cell Anodes

Carbonaceous direct fuel cells are hampered by sluggish anode kinetics associated with CO poisoning and therefore typically require a high load of costly Pt-based electrocatalysts. Direct borohydride fuel cells (DBFCs) have an inherent advantage due to the absence of CO and are characterized by high thermodynamic specific energy . Here we show for the first time, using fundamental electrochemical methods combined with fuel cell experiments, that osmium nanoparticles are kinetically superior and stable catalysts for borohydride electro-oxidation compared to Pt and PtRu. Osmium favors the direct oxidation of by a total of seven electrons as opposed to in situ hydrogen generation. The complex network of reactions involved in the oxidation of to is analyzed in the context of the experimental data. The current densities obtained with DBFC at with 20% anode were at and at .