Additional pathways for the ethanol electro-reforming knowledge: The role of the initial concentration on the product yields

Graphene-like materials as an alternative to carbon Vulcan support for the electrochemical reforming of ethanol: Towards a complete optimization of the anodic catalyst

“…In addition, Jongsomjit et al proposed a more detailed mechanism involving partially charged intermediate species from ethanol and acetaldehyde [59]. Despite the fact that the operational conditions of the ethanol electro-reforming process (80 ºC, 1 atm) vary considerably from those mentioned above, our group previously proved that this mechanism takes place also during the electrochemical process on Pt-based electrocatalysts but in a lesser extent in comparison to Cu-based catalysts [15].…”

“…Then, the higher potentials required at higher current densities (from 100 mA • cm -2 ) favor the formation of oxidized species (OH-), adsorbed mainly on the promoter (Ni) surface, which combines with the acetyl species to form acetic acid and hydrogen (Eq. 3), in the bifunctional mechanism [15,55,56]. Thus, selectivity towards acetaldehyde decreases at higher current densities, whereas selectivity towards acetic acid increases.…”

“…Conversely, selectivity towards ethyl acetate does not vary considerably, suggesting that ethyl acetate is produced in a lesser extent through non-electrochemical reactions, principally through the condensation of ethanol and acetaldehyde (Eq. 4) [15]. Global reaction mechanisms are described below [4,15,57]:…”

“…The reason of this over-faradaic hydrogen production might involve the ethyl acetate formation, which is produced exclusively by a chemical reaction route (Eq. 4), unlike acetaldehyde and acetic acid [15]. This over-faradaic hydrogen is formed in the anodic compartment of the cell and measured in the cathode by its diffusion through the membrane.…”

“…The complete oxidation of ethanol towards carbon dioxide is challenging due to the difficulty of breaking the C-C bond at low cell potentials [14]. Reaction mechanisms of ethanol electro-oxidation have been reported by some authors [15,16]. At the cathode, protons released from EOR are reduced to hydrogen.…”