Novel self-supported reduced graphene oxide foam-based CoAu electrode: An original anode catalyst for electrooxidation of borohydride in borohydride fuel cell

Abstract

Abstract An original three-dimensional self-supported reduced graphene oxide (rGO) foam is successfully prepared in this work. This novel support material, modified with Co nanosheets and Au nanoparticles, is employed as a high-performance catalyst for NaBH4 electrooxidation under alkaline condition. The surface chemical component and morphology of the catalyst is characterized by X-ray diffraction pattern, X-ray photoelectron spectroscopy, scanning electron microscope. The synthesized electrode exhibits excellent performance (1.35\u202fA\u202fcm−2 at 0\u202fV) towards NaBH4 electrooxidation. The unique structure of rGO foam caused a large electrochemical active surface area (EASA(Au)\u202f=\u202f390\u202fm2\u202fg−1), low electrochemical impedance, as well as 55.4% utilization efficiency of NaBH4. Also, catalytic kinetic parameters during the electrooxidation reaction of NaBH4 in a low NaBH4 concentration are investigated. Results indicate that oxidation of BH4− is a first-order reaction, and the exchanged number of electrons obtained at the CoAu/rGO foam electrode is 6.9. Finally, we practically apply it to a direct borohydride-hydrogen peroxide fuel cell (DBHPFC). This work suggests that the prepared rGO foam is an excellent current collector, and CoAu/rGO foam electrode is a promising anode catalyst to apply in DBHPFC.