Pd Modified MmNi50.6Co10.2Mn5.4Al1.2 Alloy as the Catalyst of NaBH4 Electrooxidation

Abstract

AbstractA Pd‐modified hydrogen storage alloy was investigated as the anode electrocatalyst of direct borohydride fuel cell. The modification of the MmNi50.6 Co10.2 Mn5.4 Al1.2 hydrogen storage alloy with Pd was carried out by a self‐reduction reaction method. The morphology and the distribution of Pd on the surface of the alloy were observed by scanning electron microscope and energy dispersive X‐ray spectrometer. It was found that Pd particles uniformly distributed on the alloy surface and the content of Pd was 0.64 wt.%. The catalytic activity of the Pd‐modified hydrogen storage alloy for NaBH4 electrooxidation was evaluated by cyclic voltammetry and chronoamperometry measurements. Results showed that Pd modification significantly enhanced the catalytic activity of the hydrogen storage alloy. In the 1.0 mol dm–3 NaOH+ 0.1 mol dm–3 NaBH4 solution, the stabilized current density at –0.7 V was 34 and 22 mA cm–2 for the pristine and the Pd‐modified alloy, respectively. The utilization efficiency of NaBH4 on the Pd‐modified alloy catalyst reached 45%, which is higher than that on the pristine alloy (30%). The number of electrons released by BH4– electrooxidation on Pd‐modified alloy was found to be close four.