Improved Electrochemical Oxidation of Polyalcohols in Alkaline Media on Palladium-Nickel Catalysts

Palladium is an efficient monoatomic catalyst for the electrochemical oxidation of polyalcohols in alkaline media, yet the oxidation rate is still slow compared to other smaller molecules. In order to improve the oxidation rate, Ni was mixed with Pd for synthesis of PdNi/C nanoparticles. The oxidation rates of ethylene glycol (EG), propylene glycol (PG), and glycerol (G) on Pd/C were compared to the oxidation rates on Pd16Ni84/C, Pd53Ni47/C, and Pd68Ni32/C. The oxidation rate of PG was enhanced by the presence of Ni as much as 14 times (Pd53Ni47/C). The oxidation rate of EG was enhanced 2.3 times on Pd68Ni32/C, and G was improved 2.9 times on Pd53Ni47/C. A significant shift in d-band center was also observed (as high as +0.11eV in Pd53Ni47/C) on each PdNi/C catalyst compared to that of Pd/C due to the presence of Ni. The correlation between increased oxidation rate and shift in d-band center is indicative of the presence of an electronic effect, which is particularly strong for PG.