Charge-controlled switchable CO adsorption on FeN4 cluster embedded in graphene

Electrical charging of an FeN4 cluster embedded in graphene (FeN(4)G) is proposed as an approach for electrocatalytically switchable carbon monoxide (CO) adsorption. Using density functional theory (DFT), we found that the CO molecule is strongly adsorbed on the uncharged FeN(4)G cluster. Our results show that the adsorption energy of a CO molecule on the FeN(4)G cluster is dramatically decreased by introducing extra electrons into the cluster. Once the charges are removed, the CO molecule is spontaneously adsorbed on the FeN(4)G absorbent. In the framework of frontier molecular orbital (FMO) analysis, the enhanced sensitivity and reactivity of the FeN(4)G cluster towards the CO molecule can be interpreted in terms of interaction between the HOMO of CO molecule and the LUMO of FeN(4)G cluster. Therefore, this approach promises both facile reversibility and tunable kinetics without the need of specific catalysts. Our study indicates that the FeN(4)G nanomaterial is an excellent absorbent for controllable and reversible capture and release of the CO. (C) 2017 Elsevier B.V. All rights reserved.