Synthesis Of Pdau/C And Pdaubi/C Electrocatalysts By Borohydride Reduction Method For Ethylene Glycol Electro-Oxidation In Alkaline Medium

Pd/C, Au/C, AuBi/C, PdAu/C, PdAuBi/C electrocatalysts (with different atomic ratios and 20 wt% of metal loading) were prepared by borohydride reduction method using a water/2-propanol mixture as solvent, Pd(NO3)(2)center dot 2H(2)O, HAuCl4 center dot 3H(2)O and Bi(NO3)(3)center dot 5H(2)O as metal sources, carbon black Vulcan XC72 as support and NaBH4 as reducing agent. The obtained electrocatalysts were characterized by energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and cyclic voltammetry. The activities of the prepared electrocatalysts for ethylene glycol electro-oxidation were investigated by chronoamperometry using the thin porous coating technique. The atomic ratios of the electrocatalysts determined by EDX were similar to the nominal values. The X-ray diffratograms of Pd/C and PdAu/C showed the presence of Pd(fcc) phase and Pd-Au(fcc) alloys, respectively. Depending on the Au content, segregated fcc Pd-rich and Au-rich phases were observed in the PdAu/C electrocatalysts. PdAuBi/C also showed the presence of fcc alloys while for Bi/C the presence of bismuth oxide phase was observed. TEM micrographs of all electrocatalysts showed a mean particle sizes in the range of 5-8 nm and a monomodal and relatively broad distribution of particle sizes. Electrochemical experiments indicate that the PdAuBi/C (50:45:05) electrocatalyst has the higher electroactivity than others obtained electrocatalysts.