Carbon Nanotube Structures as Support for Ethanol Electro-Oxidation Catalysis

Abstract

In the present study, the effect of support for ethanol electro-oxidation reaction was investigated on 20 percent Pt/C (E-Tek), 20 percent Pt/commercial CNT, and 20 percent Pt/home-made CNTs. Homemade CNTs were prepared by template synthesis method via chemical vapor deposition (CVD) method. Twenty percent Pt/commercial CNTs and 20 percent Pt/home-made CNTs were prepared by polyol method. The metal dispersions were determined from volumetric chemisorption measurements. These catalysts were tested as anode catalysts for the ethanol electro-oxidation reaction at room temperature by cyclic voltammetry. An optimization study was conducted to find out the optimum scan rate and optimum potential change for ethanol electro-oxidation reaction on 20 percent Pt/C (E-Tek) catalyst. Then, ethanol electro-oxidation measurements were performed on 20 percent Pt/C (E-Tek), 20 percent Pt/commercial CNTs, and 20 percent Pt/home-made CNTs catalysts in 0.5 M H2SO4 +0.5 M ethanol solution at 0.05 V/s scan rate and 1.2 V vs. NHE. Although the raw data indicated that the 20 percent Pt/commercial CNTs exhibited the worst performance, the performances of all of the catalysts were identical after normalizing the current values with respect to the exposed Pt site obtained from the volumetric hydrogen chemisorption measurements. These results indicate that only the metal dispersions improved ethanol electro-oxidation reaction and support did not have any effect on ethanol electro-oxidation reaction under the conditions used in this study.