Conductive Graphitic Carbon Nitride as an Ideal Material for Electrocatalytically Switchable CO(2) Capture

Good electrical conductivity and high electron mobility of the sorbent materials are prerequisite for electrocatalytically switchable CO(2) capture. However, no conductive and easily synthetic sorbent materials are available until now. Here, we examined the possibility of conductive graphitic carbon nitride (g-C(4)N(3)) nanosheets as sorbent materials for electrocatalytically switchable CO(2) capture. Using first-principle calculations, we found that the adsorption energy of CO(2) molecules on g-C(4)N(3) nanosheets can be dramatically enhanced by injecting extra electrons into the adsorbent. At saturation CO(2) capture coverage, the negatively charged g-C(4)N(3) nanosheets achieve CO(2) capture capacities up to 73.9 × 10(13) cm(−2) or 42.3 wt%. In contrast to other CO(2) capture approaches, the process of CO(2) capture/release occurs spontaneously without any energy barriers once extra electrons are introduced or removed, and these processes can be simply controlled and reversed by switching on/off the charging voltage. In addition, these negatively charged g-C(4)N(3) nanosheets are highly selective for separating CO(2) from mixtures with CH(4), H(2) and/or N(2). These predictions may prove to be instrumental in searching for a new class of experimentally feasible high-capacity CO(2) capture materials with ideal thermodynamics and reversibility.