Electrocatalytic performance of Pt–Dy alloys for direct borohydride fuel cells

• Effect of temperature and concentration on -BH4BH4- oxidation at prepared Pt–Dy alloys.
• Pt–Dy alloy with lower Pt content shows higher activity for -BH4BH4- oxidation.
• Pt–Dy alloys show higher Coulombic efficiency than Pt at higher temperatures.
• Lab fuel cell with Pt–Dy anode reaches higher power density than one with Pt anode.

The electrochemical oxidation of sodium borohydride (NaBH4) is systematically studied on platinum–dysprosium (Pt–Dy) alloys in alkaline media with respect to application in direct borohydride fuel cells (DBFCs). Using several different techniques, namely cyclic voltammetry, chronoamperometry and chronopotentiometry, reaction parameters are evaluated for NaBH4 electrooxidation in 2 M NaOH supporting electrolyte. The values obtained for the number of electrons exchanged are comparable for the two alloys and close to 2.5. Dependence of Pt–Dy alloys activity for NaBH4 oxidation on the electrolyte composition and temperature is also investigated. Test fuel cell is assembled using Pt–Dy alloy as anode, reaching peak power density of 298 mW cm−2 at current density of 595 mA cm−2 and cell potential of 0.5 V at 25 °C. Pt–Dy alloys exhibit comparable behavior with pure Pt electrode at room temperature, while at higher temperature they exhibit improved Coulombic efficiency, with the advantage of significantly lower price.