Surface-Rearranged Pd3Au/C Nanocatalysts by Using CO-Induced Segregation for Formic Acid Oxidation Reactions

Carbon-supported Pd 3 Au nanoparticle catalysts were synthesized via chemical reduction. Surface segregation of Pd in Pd 3 Au catalyst was achieved via heat treatment under air, Ar, CO–Ar, and CO atmospheres, in order to obtain a surface with changed structures and composition. The surface composition was analyzed by electrochemical methods, and the Pd surface composition was observed to increase from 67.2% (air (asp) sample) to 80.6% (CO sample) after heat treatment under a CO atmosphere. The CO-induced surface segregation of the Pd 3 Au electrocatalyst resulted in a significantly improved formic acid oxidation (from 6.93 to 18.11 mA cm –2 ) and stability (from 0.66 to 2.01 mA cm –2 ) compared to the sample prepared in air, as well as increased mass activity (from 199.20 to 520.55 A g –1 ), electrochemical surface area (ESA Pd ) (from 61.08 to 95.68 m 2 g Pd –1 ), and specific activity …