Highly Active Rupd Bimetallic Catalysts for Sodium Borohydride Electrooxidation and Hydrolysis

Abstract

In the present study, bimetallic RuPd/carbon nanotube (RuPd/CNT) electrocatalysts were synthesized at different molar ratios by sodium borohydride (NaBH4) reduction. These catalysts were characterized with advanced surface characterization techniques such as x-ray diffraction (XRD), scanning electron microscopy with energy dispersive x-ray (SEM-EDX), and x-ray photoelectron spectroscopy (XPS). The activities of these catalysts towards electrooxidation of NaBH4 and hydrogen production from hydrolysis/methanolysis of NaBH4 were investigated. According to XRD results, the particle sizes of Ru/CNT and Ru60Pd40/CNT catalysts were calculated as 3.16 and 3.05 nm, respectively. The distribution and elemental composition of Ru and Pd nanoparticles on CNT were obtained by SEM-EDX analysis. The XPS method was used to determine the oxidation states of Ru and Pd on the CNT surface. The electrochemical activities of these catalysts were determined by cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) measurements. The results show that the Ru60Pd40/CNT catalyst has the highest current mass activity with 2161.94 mA/mg Ru (12.72 mA/cm(2)) current density. Consequently, the RuPd/CNT catalyst is a promising anode catalyst for direct borohydride fuel cells (DBFC) with good stability and high activity.