Nanostructured Carbons Prepared by Ultrasonic Spray Pyrolysis

The synthesis of a new class of activated carbon materials (ACM) using ultrasonic spray pyrolysis (USP) of low-cost, materials was investigated. An aqueous solution containing sucrose and sodium carbonate or bicarbonate was ultrasonically nebulized and a flow of argon carried the droplets through a heated tubular reactor where solvent evaporation and precursor decomposition occurred. Carbons prepared from 1.0 or 5.0 M Na2CO3 or 1.0 M NaHCO3 had an outer shell and a macroporous interior. The carbon prepared from 0.1 M Na2CO3 or 0.1 M NaHCO3 appeared solid under TEM, but the substantial surface areas indicated that they were microporous. Powder XRD showed that the carbon materials were amorphous both before and after annealing at 900°C. The decrease in the concentration of Na2CO3 in the precursor mixture led to the decrease in the particle size because less CO2 was evolved that resulted in less expansion of the carbon.