Yield of high-quality SWNT has been a major barrier to applications; on conventional catalyst that lend themselves to large scale commercial production, yield is 5~6 wt% in most SWNT synthesis processes. In this research, high yield SWNT with high quality was produced using small pore Co-MCM-41 catalyst, C10 templated 3 wt% Co-MCM-41. By controlling the pH of catalyst synthesis, the prereduction temperature, and carbon monoxide per unit mass of catalyst flow rate, the carbon yield reached 34 % with 96 % of SWNT selectivity. The C10 MCM-41, with pore diameter of 1.8 nm measured by nitrogen physisorption, can accommodate more Co ions into the silica matrix than C16 MCM-41 under the same Co loading, without formation of surface oxides. The reduction stability of C10 Co-MCM-41is much higher than that of C16 Co-MCM-41, showing a very narrow temperature range for a full reduction, because of the faster ion migration at higher temperature. The SWNT produced by C10 Co-MCM-41 has two dominant diameters: 0.9 nm and 1.7 nm measured by Raman spectroscopy. By varying the pH of catalyst synthesis and the prereduction temperature of the catalyst before SWNT synthesis, the ratio of the 1.7 nm to the 0.9 nm tubes shifts systematically. The highest yield obtained in this study was 34 %; however, the yield can be further increased by optimizing the catalyst synthesis and pretreatment conditions, as well as the SWNT synthesis conditions. The metal content of product SWNT after purification by a base-acid treatment was 0.7 %, and the surface area as high as 1800 m2/g. The high yield, the low metal content, and the high surface area suggest many promising applications of SWNT in the bio-medical engineering, material science, new catalytic support, etc.

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