Amorphous NiB alloy decorated by Cu as the anode catalyst for a direct borohydride fuel cell

Abstract

In this study, amorphous NiB alloy decorated by Cu is prepared by chemical reduction. Moreover, the effect of Cu addition for the electrocatalytic activity of borohydride (BH4−) oxidation is studied. The physical characteristics of NiB or NiBCux nanoparticles are confirmed by transmission X-ray diffraction (XRD) and scanning electron microscopy (SEM). The physical characterization results demonstrate that the NiB or NiBCux nanoparticles have an amorphous structure and NiBCux nanoparticles have improved dispersity. The borohydride oxidation activity of the as-prepared catalysts is investigated by cyclic voltammetry (CV), linear scan voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). Results indicate that the NiBCux/C nanoparticles have higher electrocatalytic activity for borohydride oxidation than NiB/C, and the borohydride oxidation current of NiBCux/C nanoparticles initially increases and then decreases with the increase in Cu content. The optimum molar content of copper in the six prepared catalysts is 2.2%. It is proposed that the addition of Cu is conducive to sodium borohydride adsorption, thereby improving the electro-oxidation activity for borohydride. Hence, amorphous NiB alloy decorated by Cu can enhance the electro-oxidation performance for borohydride.