Synthesis of Ultrathin Aupt Alloy Porous Nanowires with Abundant  Electrocatalytic Active Sites for Excellent Electrocatalysts

Abstract

Development of excellent fuel cells requires ingenious design and precise regulation of the structure and composition of catalysts. This report describes a facile method for preparing gold-platinum alloy porous nanowires (AuPt PNWs) with tunable composition. This method employs uniform tellurium nanowires (Te NWs) as a sacrifice template and reductant in galvanic replacement reactions, followed by etching using NaClO. Due to the synergistic actions of the two metals and a well-designed structure containing abundant electrocatalytic active sites, the prepared AuPt PNWs showed excellent performance in electrochemical experiments using direct methanol fuel cells. The PNWs with the composition of Au 28 Pt 72 exhibited the highest activities in methanol solution, with a maximum mass current density of 1.278 A mg -1 (1.22 and 1.65 times that of Pt PNWs and commercial Pt/C, respectively). Besides, the Au 28 Pt 72 PNWs revealed good stability by retaining 85.2% of its initial mass current density after 2000 cycles. The high electrocatalytic activity at optimal composition is attributed to a suitable binding energy of methanol on the catalyst surfaces, which is supported by DFT calculations. These findings present new pathways for the engineering and preparation of enhanced electrocatalytic performance electrocatalysts in direct methanol fuel cells.

Keywords: AuPt alloy porous nanowires, Composition-tunable synthesis, Electrocatalytic performance, Density functional theory, Direct methanol fuel cells