The preparation and performance of high activity Ni-Cr binary catalysts for direct borohydride fuel cells

Ni-Cr binary anode catalysts used in direct borohydride fuel cells (DBFCs) were prepared using a constant potential electrodeposition method. Compared with pure metal Ni catalysts, the electro-oxidation currents of borohydride ions (BH ₄ ^? ) more than doubled when using Ni-Cr binary catalysts under the same conditions. The enhanced activity of the Ni-Cr binary catalysts could be attributed to the change in distribution of BH ₄ ^? ions on the surface of the Ni electrode. This is due to Cr electrodeposits, which allows a greater number of hydrogen atoms to catalyze from each tetrahedron BH ₄ ^? ion. The performance of Ni-Cr binary catalysts could also be improved by optimizing the electrodeposition conditions. The results show that Ni-Cr binary catalysts are optimally prepared using an electrodeposition method of 1s with a Cr³⁺ concentration of 0.2 mol L^?1 and a potential of ?0.100 V.