One-pot synthesis of carbonaceous monolith with surface sulfonic groups and its carbonization/activation

The carbonaceous monoliths rich in surface sulfonic acid groups were synthesized by one-pot hydrothermal carbonization of the mixture of p-toluenesulfonic acid/glucose/resorcinol at 180 °C. The Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy characterizations confirmed the presence of surface sulfonic groups on these monoliths. The catalytic performance of this kind of carbonaceous material as a solid-acid catalyst was studied in the reaction of acetalization of benzaldehyde and the results showed that it has high activity and reusability. Then, these monoliths were further carbonized and activated to form monolithic carbons with high surface area and large pore volume. The surface area and pore volume per mass increased with prolonging the activation time (0–6 h) and the best results on 6-h activated samples were 2337 m2/g and 2.12 cm3/g. Due to the decrease in bulk density the volumetric surface area increased initially until maximum and then slightly dropped down during the activation. These carbonized and activated samples showed better oxidation resistance than one commercial activated carbon under air. Moreover, the adsorption capacity for dye molecules with different size on these activated samples was significant higher than that on commercial activated carbons and a synthetic ordered mesoporous carbon.