Sodium Alginate-Assisted Synthesis of PdAg Bimetallic Nanoparticles and their Enhanced Activity for Electrooxidation of Ethanol

Abstract

Palladium and palladium-silver bimetallic nanocrystals have been synthesized hydrothermally by using environmental-friendly sodium alginate as the stabilizer and reducing agent. The pure palladium nanoparticles were spherical-like possibly due to the principle of the lowest surface energy, however, the formation of bimetallic palladium-silver nanoparticles was much more complicated, which was thinner and more irregular nanostructures than pure palladium nanoparticles. Electrochemical measurements showed that the electrocatalytic activity toward ethanol oxidation was increased first with the increase of silver content in bimetallic nanoparticles, from pure palladium of around 1070[Formula: see text]mA/mg, to PdAg-20 of 1160[Formula: see text]mA/mg and to PdAg-10 of 1750[Formula: see text]mA/mg, and declined greatly at a high content of silver, approximately 279[Formula: see text]mA/mg. Electrochemical stability test showed that PdAg-10 and PdAg-5 were the best and worst among four palladium-based samples, respectively. Based on the experimental data, the formation mechanism of pure palladium and palladium-silver bimetallic nanoparticles and the structure-property relationship of these samples have been discussed.