Transition Metals Embedded Two-Dimensional Square Tetrafluorotetracyanoquinodimethane Monolayers as a Class of Novel Electrocatalysts for Nitrogen Reduction Reaction.

The combination of transition metal (TM) atoms and high electron affinity organic framework tetrafluorotetracyanoquinodimethanes (FTCNQs) makes the TM-embedded two-dimensional (2D) square FTCNQ monolayers (TM-sFTCNQ) possible to have excellent characteristics of single-atom catalysts and 2D materials. For the first time, the TM-sFTCNQ monolayers have been considered for application in the electrocatalytic nitrogen reduction reaction (eNRR) field. Through high-throughput screening, the catalytic performance of 30 TM-sFTCNQ (TM = 3d∼5d TMs) monolayers for eNRR was comprehensively evaluated. The Mo-, Nb-, and Tc-sFTCNQ catalysts stand out with the onset potentials of -0.18, -0.44, and -0.54 V, respectively, through the optimal reaction paths. Our work will provide guidance for the green and sustainable development of electrocatalytic nitrogen fixation.