Enhanced catalytic activity of supported nanostructured Pd for the oxidation of organic molecules using γ-Fe2O3 and Fe3O4 as co-electrocatalysts

PdFe2O3/C and PdFe3O4/C electrocatalysts were evaluated for the oxidation of methanol, ethanol, ethylene glycol, glycerol and isopropanol in 1 mol L−1 KOH. The Pd-iron oxides anodes as well as Pd/C were synthesized using NaBH4 and Vulcan XC-72 as support. XRD results showed the crystalline nature of the electrocatalysts. The Pd-iron oxides anodes demonstrated a higher performance compared to Pd/C for the reactions. A comparison of the maghemite and magnetite-containing electrocatalysts indicated a similar catalytic activity considering the onset potential (Eonset). Nevertheless, PdFe2O3/C delivered slightly higher mass peak current densities in the forward scan (jf). The highest current densities were obtained from the EGOR. XPS analysis indicated the presence of Pd0 and Pd2+ species on both electrocatalyst, as well as γ-Fe2O3 and Fe3O4 (for the corresponding anode). The higher catalytic activity of PdFe2O3/C and PdFe3O4/C relative to Pd/C was attributed to the fact that maghemite and magnetite promote the reactions via the bifunctional mechanism.