Ultrathin Film PtxPd(1-x) Alloy Catalysts for Formic Acid Oxidation Synthesized by Surface Limited Redox Replacement of Underpotentially Deposited H Monolayer

Abstract

This work emphasizes the development of a green synthetic approach for growing ultrathin film PtxPd(1-x) alloy catalysts for formic acid oxidation (FAO) by surface limited redox replacement of underpotentially deposited H sacrificial layer. Up to three-monolayers-thick PtxPd(1-x) films with different composition are generated on Au electrodes and characterized for composition and surface roughness using XPS and electrochemical methods, respectively. XPS results show close correlation between solution molar ratio and atomic composition, with slightly higher Pt fraction in the deposited films. The accordingly deposited Pt42Pd58 films demonstrated remarkable specific and mass activities of up to 35 mAcm−2 and 45 Amg−1 respectively, lasting for more than 1500 cycles in FAO tests. This performance, found to be better twice or more than that of pure Pt counterparts, renders the Pt42Pd58 films comparable with the frontrunner FAO catalysts. In addition, the best alloy catalyst establishes a nearly hysteresis-free FAO CV curve a lot earlier than its Pt counterpart and thus supports the direct FAO pathway for longer. Overall, the combination of high Pd activity and CO tolerance with the remarkable Pt stability results in highly active and durable FAO catalysts. Finally, this facile and cost-effective synthetic approach allows for scaling the catalyst production and is thus appropriate for foreseeable commercialization.

Facile Synthesis of PtPd Network Structure Nanochains Supported on Multi-Walled Carbon Nanotubes for Methanol Oxidation

“…Guo et al synthesized Te nanowires via the hydrothermal method, then synthesized Pd nanowires with Te nanochains as a reducing agent and template and, finally, synthesized PtPd nanowires using ascorbic acid as a reducing agent precursor. Achari I. prepared an ultra-thin Pt x Pd (1−x) alloy catalyst by the low potential deposition of a H sacrificial layer surface, restricting redox replacement [25]. However, the reaction time required by the above-synthesized methods is relatively long and the reaction process is very complicated.…”