Synthesis of Unsupported Pt-based Electrocatalysts and Evaluation of Their Catalytic Activity for the Ethylene Glycol Oxidation Reaction

In this work, unsupported Pt, Pt-Ru (1:1 wt. % Pt:Ru ratio) and Pt-CeO2 (1:1 wt. % Pt:CeO2 ratio) electrocatalysts were synthesized and evaluated as anodes for the ethylene glycol oxidation reaction (EGOR) in out in H2SO4 electrolyte. The nanomaterials were prepared by slowly dropping the precursors in a NaBH4 solution, in a reduction process of 10 min. Analysis by XRD showed the formation of polycrystalline electrocatalysts, while the chemical composition characterization indicated a ratio between the different elements in the bimetallic materials close to the stoichiometric value. Selected area electron diffraction patterns evaluation carried out in the TEM apparatus helped in the identification of Pt (1 1 1) in the three anodes, Ru (1 0 0) in Pt-Ru, and CeO2 (1 1 1) in Pt-CeO2, confirming the formation of Ru and CeO2 phases. The results from the electrochemical characterization by Linear Scan Voltammetry (LSV) showed that the Pt-Ru material possess a higher mass catalytic activity for the EGOR, followed Pt-CeO2, compared to Pt-alone. The nano-sized Pt-Ru and Pt-CeO2 anodes demonstrated a high electrochemical stability in accelerated potential cycling tests, with very low surface area losses in the hydrogen adsorption/desorption region after 500 polarization cycles. The results indicated that the bimetallic electrocatalysts are candidate anodes for Direct Ethylene Glycol Fuel Cells.