Selective Activation of S or N-Containing Carbon Segments by Alkalic or Acidic Activators

Abstract

To date, the activation reactions of heteroatom-containing carbon segments have not been systematically studied. Here, activation of S,N dual-doped petroleum coke (SNC) by acidic (CO 2 ), alkalic (KOH and NH 3 ), and neutral (H 2 O) activators is investigated. The reactions between activators and S/N-containing segments are similar to the typical acid−base reactions. SNC exhibits higher activation reactivity as compared to the undoped carbon, thus leading to a high SSA even at low activation temperature. S-Containing groups exhibit higher reactivity to alkalic activators, and Ncontaining groups show higher reactivity to acidic activators. Compared to the activation by KOH, activation by CO 2 and NH 3 can lead to a high retention of S and N content, thus resulting in higher area-normalized capacitance in a three-electrode supercapacitor. Our results give better understanding of the activation mechanism of heteroatom-doped carbons and provide an easy method to selectively remove or keep heteroatoms during activation.

The Activated Carbon with Pyrolle-N from Cotton Stalk for the Electrochemical Performance

“…All peaks information has been summarized in Table S1. Cao et al [33] reported that AC by CO 2 activation possessed 2.5 at% of N and 5.8 at% of S, which was higher than the AC (2.17 at% N and 0.85 at% S) by KOH activation. It is clear that the physical activation avoid over consuming carbon atoms, benefiting the heteroatoms remain.…”

“…Not like the chemical activation, CO 2 activation is a green way to construct AC with micropores through adjusting the flow rate of CO 2 gas, temperature and reaction time [30][31][32] . But the yield of AC could decrease during the CO 2 consumption, and underdeveloped porous structure causes low specific surface area (SSA) of AC [31,[33][34] . Some reports had constructed AC by combining CO 2 activation with KOH activation [35,36] , but the carbon source and activation protocol leave a big unknown to the features of products.…”