Carbon-Supported Trimetallic Catalysts (PdAuNi/C) for Borohydride Oxidation Reaction

The synthesis of palladium-based trimetallic catalysts via a facile and scalable synthesis procedure was shown to yield highly promising materials for borohydride-based fuel cells, which are attractive for use in compact environments. This, thereby, provides a route to more environmentally friendly energy storage and generation systems. Carbon-supported trimetallic catalysts were herein prepared by three different routes: using a NaBH(4)-ethylene glycol complex (PdAuNi/C(SBEG)), a NaBH(4)-2-propanol complex (PdAuNi/C(SBIPA)), and a three-step route (PdAuNi/C(3-step)). Notably, PdAuNi/C(SBIPA) yielded highly dispersed trimetallic alloy particles, as determined by XRD, EDX, ICP-OES, XPS, and TEM. The activity of the catalysts for borohydride oxidation reaction was assessed by cyclic voltammetry and RDE-based procedures, with results referenced to a Pd/C catalyst. A number of exchanged electrons close to eight was obtained for PdAuNi/C(3-step) and PdAuNi/C(SBIPA) (7.4 and 7.1, respectively), while the others, PdAuNi/C(SBEG) and Pd/C(SBIPA), presented lower values, 2.8 and 1.2, respectively. A direct borohydride-peroxide fuel cell employing PdAuNi/C(SBIPA) catalyst in the anode attained a power density of 47.5 mW cm(−2) at room temperature, while the elevation of temperature to 75 °C led to an approximately four-fold increase in power density to 175 mW cm(−2). Trimetallic catalysts prepared via this synthesis route have significant potential for future development.