Hierarchical Pd and Pt structures obtained on 3D carbon electrodes as electrocatalysts for the ethylene glycol electro-oxidation

Abstract The heterogeneous surface of three-dimensional (3D) nanomaterials allows to increase the electrocatalytic activity for alcohols oxidation due to the presence of surface defects with high reactivity. In this work, 3D Pd and Pt materials were synthesized through electrodeposition directly on 3D tubular carbon porous electrodes (labeled as Pd/3D-C and Pt/3D-C) and then, used as electrocatalysts for the ethylene glycol electro-oxidation reaction (EGOR). Pd/3D-C was found in form of a hierarchical growth of Pd branched particles (∼28.5 nm) with missing rows, while Pt was in form of a thin film composed by sub 0.5 M NaOH > 0.5 M LiOH > 0.5 M H2SO4. After optimization of parameters like the KOH and EG concentration, Pd/3D-C and Pt/3D-C displayed overpotentials of 390 and 320 mV from the difference between the thermodynamic potential (0.11 V vs. RHE) and the onset potentials. Additionally, the current density was always higher in Pd/3D-C indicating a higher reactivity of its active sites. The stability tests revealed that Pd/3D-C maintained the active surface area (77.56 vs. 49.93%) and activity (112.04 vs. 39.48 %) after 500 cycles in comparison with Pt/3D-C.