New and Ultra‐Rapid Approach for Electrosynthesis of Highly Efficient Catalysts of Poly(para‐phenylenediamine) Supported Copper Oxide for Ethanol Oxidation in Alkaline Medium

Abstract

Herein, a new and simple strategy based on electrochemical cascade reactions was used to prepare copper/poly(para‐phenylenediamine). The catalysts were prepared by a facile one‐pot synthesis via an electrochemical method in a solution containing monomer and copper in a suitable concentration using potentiostatic or galvanostatic mode. Using galvanostatic mode leads to the formation of nanodendritic shape of copper hydroxide‐copper oxide in contrast with potentiostatic mode which leads to a spherical form. The response toward ethanol oxidation was greatly affected by the morphology of the obtained nanocomposite. Indeed, the current density obtained when using potentiostatic mode is about 26.55 mA cm−2 at 1.05 V vs Ag/AgCl. This performance is about 2.4 times higher than of the electrocatalyst prepared by galvanostatic mode (11.09 mA cm−2 at 0.85 V). The durability and long‐term stability of the obtained electrocatalysts were investigated using chronoamperometry and cyclic voltammetry. The decrease in current density is about 19 % and 49 % for electrocatalysts prepared by galvanostatic and potentiostatic mode respectively, after 700 scans. Finally, ex–situ FTIR spectroscopy was conducted in order to understand the reaction mechanism of ethanol oxidation in alkaline medium. It demonstrates that Cu(OH)2−Cu2O@PpPD can perform the complete oxidation of ethanol molecules, leading to the formation of CO2 molecule as the final product. This study highlighted a new simple and facile approach for synthesizing electrocatalysts based on Cu(OH)2−Cu2O@PpPD for alcohol oxidation applications.