Highly Porous Carbons Synthesized from Tannic Acid via a Combined Mechanochemical Salt-Templating and Mild Activation Strategy

Highly porous activated carbons were synthesized via the mechanochemical salt-templating method using both sustainable precursors and sustainable chemical activators. Tannic acid is a polyphenolic compound derived from biomass, which, together with urea, can serve as a low-cost, environmentally friendly precursor for the preparation of efficient N-doped carbons. The use of various organic and inorganic salts as activating agents afforded carbons with diverse structural and physicochemical characteristics, e.g., their specific surface areas ranged from 1190 m(2)·g(−1) to 3060 m(2)·g(−1). Coupling the salt-templating method and chemical activation with potassium oxalate appeared to be an efficient strategy for the synthesis of a highly porous carbon with a specific surface area of 3060 m(2)·g(−1), a large total pore volume of 3.07 cm(3)·g(−1) and high H(2) and CO(2) adsorption capacities of 13.2 mmol·g(−1) at −196 °C and 4.7 mmol·g(−1) at 0 °C, respectively. The most microporous carbon from the series exhibited a CO(2) uptake capacity as high as 6.4 mmol·g(−1) at 1 bar and 0 °C. Moreover, these samples showed exceptionally high thermal stability. Such activated carbons obtained from readily available sustainable precursors and activators are attractive for several applications in adsorption and catalysis.