Influence of Ni on the Activity of Co-Mo Electrocatalyst for Ethanol Oxidation

Abstract

Ternary as-deposited Co-Ni-Mo electrocatlyst on carbon support was investigated for the ethanol oxidation, and its activity was compared to that of bimetallic Co-Mo electrocatalyst. All electrocatalysts were prepared by electroless deposition method on carbon substrate support (CCS) made active for electroless deposition with Pd-ink. The effects of electroless deposition time, electro-oxidation temperature (30-60°C), and amount of nickel species were studied. The result showed that CoNiMo/CCS was highly active in alkaline ethanol solution (0.5M NaOH+1 M EtOH) for ethanol oxidation. The electroless deposition time, and temperature effect on the performance of the catalysts will be discussed. Although minor amount of Pd (< 50 μg/cm2) was used to make the carbon substrate active for electroless deposition, the results obtained showed that the Pd, was not utilized in ethanol oxidation. Therefore, the catalytic activity observed for the reaction is attributed to Co, Ni, and Mo, in the catalyst and not from Pd. Furthermore, the amount of nickel species affected the reaction performance significantly. Additionally, the peak current densities for the electrocatalyst with the presence of Ni species was higher than those from the bimetallic Co-Mo eletrocalalyst. This suggests that the nickel has a positive influence in the catalyst activity. Overall, this study provides a promising novel and effective non-noble Co-Ni-Mo electrocatalyst with an onset potential of -0.7 V (vs. Ag/AgCl) for electrooxidation of ethanol.