Electrodeposition of Pt-Ru nanoparticles on carbon nanotubes and their electrocatalytic properties for methanol electrooxidation

摘要

The electrochemical deposition of Pt-Ru nanoparticles on carbon nanotube electrode and their electrocatalytic properties have been investigated in this paper. Carbon nanotubes (CNTs) used in this paper are grown directly on graphite substrate by chemical vapor deposition (CVD). The Pt-Ru nanoparticles are synthesized by potentiostatic method from 0.5 M H_2SO_4 aqueous solutions with ruthenium chloride and chloroplatinic acid at - 0.25 V. The micrographs of Pt-Ru/CNT/graphite electrode are characterized by scanning electron microscopy. The electrocatalytic properties of Pt-Ru/CNT/graphite electrodes for methanol oxidation have been investigated by cyclic voltammetry in 1.0 M CH_3OH + 0.5 M H_2SO_4 aqueous solutions. The effect of ratios of Pt to Ru in the deposition bath solution on the electrocatalytical properties of Pt-Ru/CNT/graphite electrode was also investigated. The results show that the peak potential for methanol oxidation shifts to lower potential and the existing Ru can improve the stability and activity of electrode for methanol oxidation. This may be attributed to the bifunctional mechanism of Ru to Pt, which also reveals that CNTs have good potential applications as catalyst supports in direct methanol fuel cell (DMFC).