Pore-Size Control of Carbon Nanospace with Ultrasonic Irradiation
T. Ohkubo, R. Hori, K. Tsuchiya, H. Sakai and M. Abe
Tokyo University of Science, JP
activated carbon fiber, ultrasonication, micropore
In this study, we examined the micropore-size control on activated carbons by ultrasonic irradiation with various conditions.
Pitch-based activated carbon fiber (ACF; AD’ALL Co. Ltd.) was used for the sample having relatively uniform micropores whose micropore size was determined as 1.1 nm from the measurement of nitrogen adsorption isotherm at 77K and aS-plot analysis using subtracting pore effect (SPE) method for high-resolution aS-plot. Also, the ultrasonic irradiations to ACF were carried out in the water bath with various irradiation times and at three irradiation frequencies (40 kHz, 200 kHz, and 1 MHz).
The results of nitrogen adsorption isotherms indicate that we can decrease the pore volume and average pore widths of ACFs with longer irradiation time. Also, we examined the dependences of ultrasonic frequencies on micropore-size control by irradiating for 40 min. The average pore width of ACF irradiated by 40 kHz was decreased by 0.11 nm from the original one. These results suggest that the micropores of ACF are collapsed by the shock generated as a result of sonication. Besides larger pores are more easily collapsed selectively.
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Nanotech 2006 Conference Program Abstract