The Combination of Bipolar Electrolytic and Galvanic Method to Synthesize CuPt Nano-Alloy Electrocatalyst for Direct Ethanol Fuel Cell

CuPt nano alloy-particles were successfully synthesized by a combination of the methods of bipolar electrolytic and galvanic replacement. Cu2O nanoparticles prepared by a bipolar electrolytic method were used as the sacrificial templates for galvanic replacement reactions with H2PtCl6 solutions. The size of Cu2O nanoparticles was optimized by changing the electrolytic parameters to obtain fine nanoparticles. SEM and TEM analyses showed that Cu2O nanoparticles were grown in a crystal shape with a grain size of about 100 nm. The XRD results indicated that Cu2O nanoparticles were grown in a face-centered cubic structured crystal. The effects of the amount of H2PtCl6 solution on the structure, morphology, composition and electrocatalysis of CuPt were investigated. The phase analysis by XRD showed the presence of CuPt crystalline phases with a rhomb-centered structure. The SEM images indicated that the crystalline shape of Cu2O was turned into a spherical shape with the size expanded to 140 nm after galvanic reaction. The absorption analysis showed that there was one absorption peak at a wavelength of 500 nm for Cu2O while no absorption peak was observed for CuPt alloys. Additionally, compositional analysis by EDX showed that the main components of the alloys were Cu and Pt. The presence of O on the samples indicated that the galvanic reactions were not complete. The cyclic voltammetry measurement showed that CuPt nano alloy-particles exhibit better ethanol oxidation in an alkali medium compared with bare Pt.