Fast improved polyol method for synthesis of Pd/C catalyst with high performance toward ethanol electrooxidation

Abstract

Highly dispersed palladium nanoparticles that are successfully decorated on the charcoal activated carbon by a rapid and simple improved polyol method in Ethylene Glycol (EG) media in the presence of ethanolic sodium hydroxide, without any protection by capping agent, is proposed for the first time in this paper. Along this process, H2PdCl4 in ethylene glycol media can be reduced to metallic palladium at 40°C in the presence of alcoholic sodium hydroxide. Therefore, it can be claimed that ethanolic sodium hydroxide is behaving like a mild reducing agent in the EG media. Pd/C catalysts are also synthesized using improved and traditional methods for comparison. Catalysts synthesized in two different ways were characterized by Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The results illustrated that Pd/C synthesized using the improved polyol method had better dispersity and its diameter was equal to 8–10 nm which was lower compared to the conventional polyol method. The electrocatalytic performance of both Pd/C catalysts synthesized by two methods was investigated by cyclic voltammetry and chronoamperometry in the solution of 1.0 M EtOH +1.0 M NaOH at room temperature. The results showed that the Pd/C catalyst synthesized by the improved method had a significantly enhanced the activity and durability for Ethanol Oxidation Reaction (EOR) that can be related to the good dispersity of Palladium nanoparticles over support due to the improved polyol method.