Abstract

DING, Keqiang. The Electrocatalysis of Multi-walled Carbon Nanotubes (MWCNTs) for Oxygen Reduction Reaction (ORR) in Room Temperature Ionic Liquids (RTILs). Port. Electrochim. Acta [online]. 2009, vol.27, n.2, pp.165-175. ISSN 0872-1904.

Oxygen reduction reaction (ORR) was investigated on a multi-walled carbon nanotubes (MWCNTs)-modified edge plane pyrolytic graphite (EPPG) electrode using cyclic voltammetry (CV) in three kinds of room temperature ionic liquids (RTILs), i.e., 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF₄), 1-n-propyl-3-methylimida-zolium tetrafluoroborate (PMIBF₄), and 1-n-butyl-3-methylimidazolium tetrafluoro-borate (BMIBF₄). The results demonstrated that, after being modified by MWCNTs on the EPPG electrode, both the reduction peak current of oxygen and the oxidation peak current of superoxide anion were all dramatically increased, and the values of standard rate constant, κ_s, corresponding to ORR, were greatly enhanced. Under the same condition, in PMIBF₄, MWCNTs-modified EPPG electrode exhibited the most satisfied electrocatalysis for ORR, in which standard rate constant, κ_s, was improved from 2.9 × 10^-3 cm s^-1 on a EPPG electrode, to 10.4 × 10^-3 cm s^-1. While in EMIBF₄ and BMIBF₄, after being modified by MWCNTs, the value of κ_s was increased from 4.3 × 10^-3 to 8.3 × 10^-3 and 2.3 × 10^-3 to 4.2 × 10^-3 cm s^-1, respectively. For the catalysis of MWCNTs-modified EPPG electrode towards ORR, the enhanced surface area of electrode and the increased amount of “defect” sites on electrode were thought to be the main reasons for our obtained results.

Keywords : multi-walled carbon nanotubes (MWCNTs); room temperature ionic liquids (RTILs); oxygen reduction reaction (ORR); graphite electrode.

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