Effects of Different Carbon Nanotube Supported Catalysts on Methanol and Ethanol Electro-Oxidation
- PDF / 450,457 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 104 Downloads / 212 Views
1213-T08-17
Effects of Different Carbon Nanotube Supported Catalysts on Methanol and Ethanol Electro-Oxidation
Raghavendar Reddy Sanganna Gari1, Zhou Li2, and Lifeng Dong1 1
Department of Physics, Astronomy, and Materials Science, 2Greenwood Laboratory School, Missouri State University, Springfield, MO 65897, U.S.A. ABSTRACT In this work, Pt and Pt-Ru nanoparticles were synthesized on both single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). Effects of different nanotube supports on electrocatalytic activity of Pt and Pt-Ru nanoparticles for methanol and ethanol oxidations were investigated using cyclic voltammetry and electrochemical impedance spectroscopy. In comparison to MWCNTs, SWCNT supported Pt and Pt-Ru catalysts demonstrate better electrocatalytic activities in terms of forward peak current density, the ratio of forward peak current density to reverse peak current density, and charge transfer resistance. This study indicates that SWCNTs can serve as effective catalyst supports for both direct methanol and ethanol fuel cells. INTRODUCTION Alternative energy conversion systems are receiving great attention due to the depletion of fossil fuels and increasing pollution of the environment [1]. Due to excellent features like high energy density, low operating temperature, and high energy conversion efficiency, direct methanol and ethanol fuel cells are promising power sources to solve future energy problems [2]. However, their performances are limited by low electrocatalytic activity of anodes for methanol or ethanol oxidations and high cost of noble metal catalysts such as platinum (Pt) and platinumruthenium (Pt-Ru). Recently, both single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) have been demonstrated as desirable catalyst supports to improve catalytic activity and to reduce the cost by improving the dispersion of catalysts [4 - 6]. However, there is a lack of systematic comparison between SWCNTs and MWCNTs as catalyst supports for both methanol and ethanol electro-oxidation. The primary aim of this work is to investigate differences between SWCNTs and MWCNTs as catalyst supports and to study their effects on the electrocatalytic activity of Pt and Pt-Ru nanoparticles for methanol and ethanol electrooxidations. EXPERIMENT Synthesis of Pt and Pt-Ru nanoparticles on carbon nanotubes Pt/CNT and Pt-Ru/CNT catalysts were synthesized by an ethylene-glycol (EG) reduction method, which was described in details elsewhere [7-8]. Briefly, carbon nanotubes were suspended in EG solution followed by sonication for 30 minutes. Hexacholoroplatinic acid was added into the solution and mechanically stirred for 2 hrs. NaOH was added to regulate the pH of the solution to 13, and then the solution was fluxed at 130 °C for 3 hrs under argon gas flow. The precipitation was filtered, washed four times with DI water, and dried in an oven at 80 °C
for 12 hrs. The procedure for the synthesis of Pt-Ru/CNT catalysts is the same as for Pt/CNT catalysts, except we added bo
Data Loading...
