Qualitative and Quantitative Assessment of the SWNT Produced by the Controlled Catalytic Production Before and After Purification

FRANCISCO POMPEO; LEANDRO BALZANO; HARRY BARRAZA; JOSE HERRERA; EDGAR O´REAR; SOREN DAHL; WALTER ALVAREZ; DANIEL RESASCO

Postdam - Germany

Workshop; International Workshop on the Science and Application of Nanotubes; 2001

The quantification of the SWNT yield and the evaluation of their chemical characteristics are essential components in the development of a production process. In this particular study, the SWNT were produced by vapor-phase disproportionation of CO over a heterogeneous catalyst. Temperature programmed oxidation has been used to determine the total carbon yield as well as the selectivity to SWNT. The results of this quantitative method were corroborated by Raman and TEM/SEM analysis. After the SWNT production, the materials were subjected to purification steps that involve attack of the catalyst support and metals with a combination of basic and acid solutions. This process results in a different degree of functionalization of the tubes. The characterization of the chemical nature of the resulting functional groups was conducted by XPS and FTIR. To quantify the density of functional groups a combination of TPD-TPO and XPS was employed. The response of the tubes prepared by the catalytic method to the basic/acid attacks was compared to those of tubes prepared by other methods (arc discharge and laser ablation). Also, the structure of these tubes (bundle diameter, tube diameter, tube length), as measured by AFM, TEM and Raman, was compared to those commercially available.