Charge and spin communication between dual metal single-atom sites on C2N sheets: regulating electronic spin moments of Fe atoms for N2 activation and reduction

Abstract

Single-atom catalysts (SACs) with high site density provide the promising potential to significantly improve the performance of electrocatalysis, such as the nitrogen reduction reaction (NRR). However, the catalytic behaviour with interaction between individual single transition metal (TM) atom sites is particularly elusive due to its complexity. Using first-principles calculations, herein, we demonstrated the origin of enhancement of the NRR activity of Fe SACs by the adjacent single-TM atoms anchored on natural cavities of C₂N sheets. The charge and spin communication constructed between Fe and TM dual single-atom sites and p-block C₂N sheets significantly regulated the electronic spin moments of Fe atom active sites, although a large distance of about 7.5 Å exists between them and this regulation effect became more prominent after N₂ adsorption. As a result, the reduced spin moments of Fe atoms attached to N₂ can largely enhance NRR catalytic activity and selectivity towards NH₃ production, with low limiting potentials of −0.76, −0.76, −0.68, and −0.74 V for TM = Fe, Ag, Mo, and Zn, respectively, compared to that of an isolated Fe SAC (−1.04 V). The present study highlights the distinct interaction between single-atom sites that regulates the spin state of active atomic sites, and provides a new way for the design of efficient SACs.