Effect of electrochemical activation on the performance and stability of hybrid (PPy/Cu2O nanodendrites) for efficient ethanol oxidation in alkaline medium

One of the most challenges in Direct Ethanol Fuel Cell (DEFC) is to prevent the poisoning of the surface of the electrode due to the slow kinetics of ethanol oxidation reaction. Herein, we report the development of a new catalysts for ethanol oxidation using a well-defined Cu2O nanodendrites (Cu2O-NDs) supported on polypyrrole film (PPy) using a simple electrochemical approach. The effect of regeneration of the electrocatalyst in acidic medium on the performance of ethanol electro-oxidation was reported for the first time. Fourier Transform Infrared (FTIR), X-ray diffraction (XRD), Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) were used to characterize the new catalysts. The SEM and TEM images confirm that the octahedral shape of Copper oxide is converted to a dendritic one after the regeneration of the catalyst. The electrochemical behavior of the prepared catalysts towards the oxidation of ethanol were investigated by Cyclic voltammetry (CV), Chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). The current obtained by CV measurements on Cu2O-NDs/PPy/CPE was about 4 mA cm−2 which is 1.77 time higher than Cu2O/PPy/CPE catalyst (2.25 mA cm−2) with a shift of 60 mV and 150 mV in anodic and onset potential respectively demonstrating a good catalytic performance for ethanol oxidation. The stability test shows that the Cu2O-NDs/PPy/CPE loses only 7.25% of its initial current after 1000 cycles. Finally, Ex–situ FTIR spectroscopy was conducted in order to understand the reaction mechanism. Interestingly, our ex-situ FTIR results demonstrated that the ethanol oxidation mechanism displayed shape dependent behavior of copper oxide, indicating that the ethanol molecules are totally oxidized on the Cu2O-NDs leading to the formation of CO2 molecule as final product. [Display omitted] •Cu2O-NDs/PPy catalyst was synthesized by a simple electrochemical method.•The regeneration of Cu2O influences their catalytic performances towards EOR.•Cu2O-NDs/PPy displayed a higher catalytic activity towards EOR.•Cu2O-NDs/PPy is more efficient in breaking the CC bond than Cu2O/PPy.