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The calcined SBA-15 was impregnated with aqueous solutionof sucrose containing sulfuric acid, similarly to the synthesis ofCMK-18 except for the different amounts of sucrose and H2SO4.Briefly, 1 g of SBA-15 was added to a solution obtained bydissolving 1.25 g of sucrose and 0.14 g of H2SO4 in 5 g of H2O.The mixture was placed in a drying oven for 6 h at 373 K, andsubsequently the oven temperature was increased to 433 K andmaintained there for 6 h. The sample turned dark brown or blackduring the treatment in the oven. The silica sample, containingpartially polymerized and carbonized sucrose at the present step,was treated again at 373 and 433 K using the same drying ovenafter the addition of 0.8 g of sucrose, 0.09 g of H2SO4 and 5 g ofH2O. The carbonization was completed by pyrolysis with heatingto typically 1173 K under vacuum. The carbon-silica compositeobtained after pyrolysis was washed with 1 M NaOH solution(50 vol % ethanol-50 vol % H2O) twice at 373 K or 5 wt %hydrofluoric acid at room temperature, to remove the silicatemplate. The template-free carbon product thus obtained wasfiltered, washed with ethanol, and dried at 393 K. The energydispersiveX-ray and thermogravimetric analyses showed that thesilica content in the product was normally less than 5 wt % afterthe first washing with the NaOH solution. The second washinggave only trace amounts of silica, indicating that the treatmentwith NaOH or HF removed almost all of the silica.
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