Formation of Platinum Monolayer on Carbon-Supported Pd-Ru Electrocatalysts for Oxygen Reduction Reaction in Acidic Electrolytes

• Main Authors: Sun, Yu, 孫佑
• Other Authors: Wu, Pu-Wei
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/73601037395735824591

碩士 === 國立交通大學 === 工學院加速器光源科技與應用碩士學位學程 === 103 === Nanoparticles of PdRu, Pd3Ru, and Pd9Ru are synthesized and impregnated on carbon black via a wet chemical reflux process. X-ray diffraction patterns of the as-synthesized samples, PdxRu/C (x=1/3/9), suggest succesful formation of alloy without presence of individual Pd and Ru nanoparticles. Images from transmission electron microscope confirm irregularly-shaped nanoparticles with average size below 3 nm. Analysis from extended X-ray absorption fine structure on both Pd and Ru K-edge absorption spectra indicate that Ru atoms are enriched on the surface of PdxRu/C. Among these samples, the Pd9Ru/C exhibits the highest electrocatalytic activity for oxygen reduction reaction (ORR) in an oxygen-saturated 0.1 M aqueous HClO4 solution. Subsequently, the Pd9Ru/C undegoes Cu under potential deposition, followed by a galvanic displacement reaction to deposit a Pt monolayer on the Pd9Ru surface (Pd9Ru@Pt). The Pd9Ru@Pt reveals better ORR performance than that of Pt, reaching a mass activity of 0.38 mA μg-1Pt, as compared to that of commercially available Pt nanoparticles (0.11 mA μg-1Pt). In addition, a four-electron mechanism is responsible for the ORR actions occurring on the Pd9Ru@Pt/C. In the stability test, the Pd9Ru@Pt/C demonstrates a loss of 50 % in the mass activity after employing CV scans for 10,000 cycles in 0.1 M aqueous solution, indicating a large room for improvement. This core-shell Pd9Ru@Pt electrocatalyst represents a substantial reduction in the amount of Pt consumption and hence the raw material cost.