Ag-Ni nanoparticles supported on multiwalled carbon nanotubes as a cathode electrocatalyst for direct borohydride-hydrogen peroxide fuel cells

In this study, an Ag-Ni electrocatalyst supported on multiwalled carbon nanotubes (MWCNTs) was investigated to develop a new type of cathode electrocatalyst for direct borohydride-hydrogen peroxide fuel cells (DBHPFCs). Monometallic electrocatalysts consisting of Au, Ag, or Ni have previously demonstrated relatively high catalytic activity and selectivity. The characteristics of each catalyst (Au/MWCNTs, Ag/MWCNTs, and Ni/MWCNTs) were determined through various techniques, such as scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray diffraction; additionally, their performance was evaluated using a fuel cell test. Based on the results, Ag and Ni were selected to construct a bimetallic electrocatalyst, owing to their relatively superior catalytic selectivity at high current densities. Ag-Ni/MWCNT catalysts with various atomic percentage ratios were prepared, and their characteristics were investigated. Among the bimetallic electrocatalysts, Ag41Ni59/MWCNTs exhibited the highest maximum power density. Furthermore, Ag41Ni59/MWCNTs exhibited good catalytic selectivity even at high operating temperatures. The prepared Ag-Ni bimetallic electrocatalyst has moderate catalytic activity and selectivity and is more cost effective than Au and Ag catalysts; therefore, it can be used as a new type of cathode electrocatalyst for DBHPFCs.