A green trace K2CO3 induced catalytic activation strategy for developing coal-converted activated carbon as advanced candidate for CO2 adsorption and supercapacitors

Aiming to enhancing porosity development and reducing the dosage of activation agents in preparation of activated carbon, a novel green and efficient strategy of trace K 2 CO 3 induced catalytic activation was proposed. In the design, adding small amount of K 2 CO 3 (less than 2% weight ratio of precursor) can significantly reduce the reaction barrier between coal framework and CO 2 molecules, thus enhancing pore formation of as-obtained activated carbons. The resulting Ca_AC-1 has short range ordered microcrystalline structure and developed pore structure, even superior to the activated carbon from chemical activation with large dosage of K 2 CO 3 (three times weight ratio of carbon precursor). Evaluated as CO 2 adsorbent, Ca_AC-1 a high CO 2 adsorption capacity and adsorption-regeneration cycling stability. More importantly, Ca_AC-1 with optimized pore and crystalline structure can deliver excellent supercapacitive performances in term of high energy and power densities (26–35 Wh/kg at 0.338–6.25 kW/kg in organic system) as well as 100% cycling stability. Both experiment and density functional theory (DFT) calculations demonstrate that C-O-K structure can be regenerated in CO 2 activation, leading to continuously catalytic effects despite low-dose K 2 CO 3 addition. Combining the low-cost sources, simple preparation procedures and good application performances, the resulting activated carbon holds great potentials for scalable production and applications. Such strategy can also be extented for developing high-performance activated carbons from various kinds of solid carbon sources.