Gold-based bimetallic electrocatalysts supported on multiwalled carbon nanotubes for direct borohydride–hydrogen peroxide fuel cell

Abstract

Au-based bimetallic electrocatalysts supported on multiwalled carbon nanotubes (MWCNTs) were investigated to improve the selectivity and activity of the catalysts for direct borohydride–hydrogen peroxide fuel cells (DBPFCs). Au–Pd and Au–Ni catalysts were used as the anode and cathode catalysts, respectively. The Au-based bimetallic catalysts with various atomic percentage ratios were investigated using inductively coupled plasma optical emission spectroscopy, transmission electron microscopy, Brunauer–Emmett–Teller analysis, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and fuel cell tests. Among the Au-based bimetallic catalysts, Au49Pd51/MWCNTs was found to be the most suitable for the anode and Au74Ni26/MWCNTs was the most suitable for the cathode. The effects of the operating temperature and operation time on the catalytic selectivity and activity were also investigated to evaluate the performance of the bimetallic catalysts. It was found that the Au-based bimetallic catalysts had good catalytic selectivity and activity even at an elevated operating temperature and a maximum power density of 279.5 mW/cm2 was obtained at 52.0 ± 2.0 °C when Au49Pd51/MWCNTs (anode) and Au74Ni26/MWCNTs (cathode) were used for the DBPFC electrodes. It was also found that the Au-based bimetallic catalysts showed stable performance for 70 min. Thus, the Au-based bimetallic catalysts can be widely used for DBPFCs.