▎ 摘　　要

We for the first time report the discovery of a series of highly efficient electrocatalysts, i.e., transition metals anchored on N/O-codoped graphene, for nitrogen fixation via high-throughput screening combined with first-principles calculations. The catalytic performance can be effectively modulated by coordination engineering. Among 10 representative electrocatalysts (i.e., V-N-4@Gra, Tc-N-4@Gra, V-O1N3@Gra, V-O2N2 alpha@Gra, V-O2N2 beta@Gra, V-O2N2 gamma@Gra, V-O3N1@Gra, Mo-O3N1@Gra, V-O-4@Gra and Ru-O-4@Gra), V-O2N2 gamma@Gra possesses the lowest Delta G(max) of 0.38 eV. Molecular dynamics simulation results indicate that all the predicted TM-OxNy@Gra (x + y = 4) have high stabilities and can be used as electrocatalysts under practical reaction conditions. The more charge on the adsorbed N-2, the longer the N-N bond length and the greater the activation of N-2. Interestingly, the linear combination of adsorption energy of different intermediates, i.e., Delta E-ads[(*N-2 - *N) + (*NNH - *N) + (*NH2 - *N)], can be used as a good descriptor to unveil the structure-property relations, and V-O2N2 gamma@Gra possessed moderate adsorption energy, so it exhibits the highest catalytic activity for the electrocatalytic nitrogen reduction reaction (eNRR) among all investigated materials. Overall, through coordination engineering, the coordination environment and electronic structure of the active centers can be modulated properly, thereby regulating the catalytic activity effectively. We expect that our work will provide new insights into the rational design of electrocatalysts and effective modulation of the catalytic performance via coordination engineering. The present study opens up an important route for the development of efficient catalysts for the eNRR, and will inspire the follow-up experimental and theoretical efforts in this direction.