Investigation of carbon supported RuPt nanoparticles for high-performance electrocatalytic oxidation of methanol

Abstract

Platinum-nanoparticle-based catalysts are fascinating and widely used in fuel cells. This study is an attempt to develop low-cost and high performance of carbon supported Ru-Pt nanoparticles (NPs) for direct methanol fuel cells (DMFCs). We have synthesized RuPt/C, Ru@Pt/C, RuPt/MWCNT, and Ru@Pt/MWCNT nanomaterials by a facile two-step reduction method. X-ray diffraction (XRD) shows the f.c.c. Pt and h.c.p. Ru phases and the NPs are under a slight compressed strains. The synthesized NPs obtained small mean sizes (dmean ≤ 3.9 nm) and narrow size distributions (1 – 9 nm). STEM-EDS line scan profiles reveal that architecture of Ru@Pt NPs composes of Ru-core and Pt-rich–Ru alloy shell, while that of RuPt alloy NPs exhibits random arrangement of Ru and Pt atoms. The Ru@Pt/MWCNT possessed the highest methanol oxidation activity with current density (Jf) of 182.4 mA.cm-2 and the lowest electron transfer resistance (Ret) of 606 Ω as compared with the other samples. The outstanding performance of Ru@Pt/MWCNT could be attributed to the high Pt dispersion, the strong synergetic effect of the Ru@Pt NPs (i.e. improving CO poisoning tolerance and enhancing the intrinsic activity of Pt), and the high porosity and electrical conductivity of MWCNT support.