Yttria stabilized and surface activated platinum (PtxYOy) nanoparticles through rapid microwave assisted synthesis for oxygen reduction reaction. (April 2018)

• Record Type: Journal Article
• Authors: Sandström, Robin; Gracia-Espino, Eduardo; Hu, Guangzhi; Shchukarev, Andrey; Ma, Jingyuan; Wågberg, Thomas
• Is Part Of: Nano energy. Volume 46(2018)
• Page Start: 141
• Page End: 149
• Publication Date: 2018-04
• Subjects: Yttrium -- Platinum -- Nanoparticles -- Catalysis -- Hydrogen fuel cells -- Oxygen reduction; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2018.01.038
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: The enhancement of platinum (Pt) based catalysts for the oxygen reduction reaction (ORR) by addition of rare earth metals represents a promising strategy to achieve high activity yet low content of the precious metal and concurrently addresses stability issues experienced by traditional late transition metal doping. Improvement in Pt utilization is essential for vehicular applications where material cost and abundancy is a great concern. Here we report a fast and efficient production route of yttria-stabilized platinum nanoparticles (Ptx YOy ) using a conventional household microwave oven. ORR performance showed a significant improvement and an optimum activity at a 3:1 Pt:Y ratio outperforming that of commercial Pt-Vulcan with a doubled specific activity. Incorporation of Y is evidenced by extended X-ray absorption fine structure and energy dispersive X-ray analysis, while significant amounts of integrated Y2 O3 species are detected by X-ray photoelectron spectroscopy. Density functional theory calculations suggest surface migration and oxidation of Y, forming stable superficial yttrium oxide species with low negative enthalpies of formation. The robustness of Ptx YOy is shown experimentally and through theoretical arguments demonstrating that surface yttria acts as an stabilizing agent and promoter of highly active ORR sites on the remaining Pt surface, surpassing even the Pt3 Y alloy configuration. Graphical abstract: fx1 Highlights: Rapid microwave based synthesis of novel Ptx YOy based nanoparticles firmly anchored to a carbon support. Y-incorporation leads to dramatic morphological changes of the nanoparticles. Nearly doubled specific activity of Pt3 YOy /C compared to Pt/C toward oxygen reduction. Surface migration and passivation of Y atoms leaves behind highly active sites responsible for enhanced ORR activity that in addition acts as a stabilizing agent as evidenced by ab initio density functional theory calculations.