An electrochemical method to prepare of Pd/Cu₂O/MWCNT nanostructure as an anode electrocatalyst for alkaline direct ethanol fuel cells

This study reports an electrochemical method to fabrication of palladium nanoparticles (Pd NPs) promoted with cuprous oxide (Cu₂O) supported on multi-walled carbon nanotube (Pd/Cu₂O/MWCNT). First, Cu₂O is electrodeposited on treated MWCNTs in the optimum deposition conditions. Then, the Pd nanostructure is electrochemically fabricated on Cu₂O/MWCNT electrode by cycling the potential between +0.5 to −1.0 V in negative direction. The prepared electrodes are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). The electrocatalytic performance of Pd/Cu₂O/MWCNT electrocatalyst for ethanol oxidation reaction (EOR) is investigated by cyclic voltammetric (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA) measurements. The formation of the Pd/Cu₂O/MWCNT is confirmed by EDX and XRD techniques. The onset potential of Pd/Cu₂O/MWCNT shifts to negative values by 120 mV compared to the onset potential of Pd/MWCNT. Much higher I_f/I_b value is obtained for Pd/Cu₂O/MWCNT compared to other Pd-based catalysts indicating Cu₂O could significantly enhance the stability and CO poisoning tolerance of the Pd towards ethanol electrooxidation. The results revealed that the prepared Pd/Cu₂O/MWCNT catalyst can be a promising anode catalyst for alkaline direct ethanol fuel cells.