Evaluation of Co–Au bimetallic nanoparticles as anode electrocatalyst for direct borohydride-hydrogen peroxide fuel cell

Carbon-supported Co–Au bimetallic nanoparticles with different Co/Au atomic ratios were prepared through two-step reduction in a reverse microemulsion system. The prepared catalysts were investigated as anode electrocatalysts for the electrooxidation of borohydride through X-ray diffractomer, transmission electron microscopy, cyclic voltammetry, chronoamperometry, chronopotentiometry, electrochemical impedance spectroscopy (EIS), and fuel cell test. Results showed that the Co4–Au1/C catalyst presents the highest catalytic activity and the lowest electrochemical impedance for BH4− electro-oxidation with the electron-transfer number of 4.1 among all the resultant catalysts. In addition, a laboratory direct borohydride-hydrogen peroxide fuel cell (DBHFC) with Co4–Au1/C anode obtains the maximum power density as high as 102.4 mW cm−2, which was 2.14 times that obtained when Au/C catalyst was used. All these results are indicating that the Co4–Au1/C is an efficient anode catalyst for direct borohydride-hydrogen peroxide fuel cell.