GOLD-NICKEL-RHENIUM-PHOSPHORUS CATALYSTS FOR EFFICIENT SODIUM BOROHYDRIDE OXIDATION

Fuel cells are being actively investigated as an attractive alternative energy source for cleaner power generation. One type of fuel cell, the direct borohydride fuel cell (DBFC), is being developed especially for portable power supply. Since sodium borohydride is used as fuel, the development of electrocatalysts with reasonable cost and a high electroactivity towards sodium borohydride oxidation (BOR) is of considerable interest for fuel cells. In this study, gold-nickel-rhenium-phosphorus catalysts deposited on the surface of copper (Au-NiReP/Cu) were investigated as catalysts for the BOR. The Au-NiReP/Cu catalysts were obtained by a two-step process involving the electroless deposition of the NiReP coatings on the Cu surface, followed by the deposition of Au crystallites using the galvanic displacement technique. The morphology, structure and composition of the resulting catalysts were examined by Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray Analysis (EDX), and Inductively Coupled Optical Emission Spectroscopy (ICP-OES). Cyclic voltammetry (CV) and chronoamperometry (CA) were used to determine the electrocatalytic activity of the prepared Au-NiReP/Cu catalysts towards the BOR in alkaline medium. It was found that the NiReP coatings deposited on the Cu surface have a typical globular morphology consisting of smaller nodules. The Au crystallites with the size of 10-50 nm were deposited on the as-prepared NiReP/Cu catalysts by immersing them in the 1 mM HAuCl\(_{4}\) + 0.1 M HCl solution at room temperature for 1, 2, and 5 min, respectively. The as-prepared Au-NiReP/Cu catalysts exhibited a higher electrocatalytic activity toward the BOR as compared with that of a bulk Au and NiReP/Cu electrode, and seem to be a promising anodic material for DBFC. This research was funded by a grant (No. P-MIP-23-467) from the Research Council of Lithuania.