Insights on the electrooxidation of ethanol with Pd-based catalysts in alkaline electrolyte

Abstract

In this work, we report a facile method of synthesis of carbon supported Pd, PdRu, and PdNi nanoparticles, and a comparative study of their catalytic behavior for the electrooxidation of ethanol in alkaline media. The addition of metals such as Ru or Ni increases the oxophilicity of the Pd surface, as observed from the shifting of the Pd oxide reduction peaks. As a consequence, the onset potential for the electrooxidation of ethanol shifts to less positive values on the bimetallic catalysts. The nature and evolution of the species formed during the electrooxidation of ethanol over the catalysts under study has been monitored using in situ infrared spectroscopy. In order to assess properly the evolution of the species formed during the electrooxidation of ethanol, infrared spectra have been recorded in both H2O and D2O electrolytes. The results presented in this work demonstrate that the scission of the C–C bond of ethanol takes place at the surface of Pd/C and PdM/C (M = Ni and Ru) at potentials as low as 30 mV. However, at potentials above E ≥ 400 mV, acetates are the main species formed during the electrooxidation of ethanol.