We systematically investigated the catalytic performance of 3d, 4d, and 5d transition metals anchored onto two-dimensional extended porphyrin (PP) substrates as nitrogen reduction reaction (NRR) electrocatalysts, employing density functional theory (DFT) calculations and four-step high-throughput screening. Four novel metalloporphyrin (MPP, M = Zr, Nb, Hf, and Re) single-atom catalyst candidates have been identified due to their excellent catalytic performance (low onset potential, high stability, and selectivity). Through comprehensive reaction path search, the maximum Gibbs free energy changes for NRR on the ZrPP (enzymatic-consecutive hybrid path), NbPP (consecutive path), HfPP (enzymatic-consecutive hybrid path), and RePP (distal path) catalysts are 0.38, 0.41, 0.53, and 0.53 eV, respectively. Band structures, projected density of states, and charge/spin distributions show that the high catalytic activity is due to significant orbital hybridizations and charge transfer between N₂ and MPP catalysts. We hope our work will promote experimental synthesis of these NRR electrocatalysts and provide new opportunities to the electrochemical conversion of N₂ to NH₃ under ambient conditions.

We for the first time systematically studied the structures and electrochemical nitrogen reduction reaction properties of two‐dimensional single transition‐metal anchored square tetracyanoquinodimethane monolayers (labeled as: TM‐sTCNQ, TM = 3d, 4d, 5d series transition metals) by employing density functional theory method. Through high‐throughput screenings and full reaction path researches, two promising electrochemical nitrogen reduction reaction catalysts Nb‐sTCNQ and Mo‐sTCNQ have been obtained. The nitrogen reduction reaction onset potential on Nb‐sTCNQ is as low as −0.48 V. Furthermore, the Nb‐sTCNQ catalyst can quickly desorb NH₃ produced with a free energy of 0.65 eV, giving Nb‐sTCNQ excellent catalytic cycle performance. The high catalytic activity of the two materials might be attributed to the effective charge transfer between the active center and adsorbed N₂, which enables the active center to adsorb and activate inert N₂ molecules well, and the reduction processes require small energy input (i.e., the maximum free energy changes are small). This work provides insights for finding highly efficient, stable, and low‐cost nitrogen reduction reaction electrocatalysts. We hope our results can promote further experimental and theoretical research of this field.

We investigate the slow-motion and weak-field approximation of the general ghost-free parity-violating (PV) theory of gravity in the parametrized post-Newtonian (PPN) framework and derive the perturbative field equations, which are modified by the PV terms of this theory. The complete PPN parameters are obtained by solving the perturbative field equations. We find that all the PPN parameters are exactly the same as those in general relativity, except for an extra parameter κ, which is caused by the new curl-type term in the gravitomagnetic sector of the metric in this theory. We calculate the precession effects of gyroscopes in this theory and constrain the model parameters by the observations of the Gravity Probe B experiment.

In this research, we systematically investigated the reaction mechanism and electrocatalytic properties of transition metal anchored two-dimensional (2D) porphine-fused sheets (TM-Por) as novel single-atom catalysts (SACs) for the electrochemical nitrogen reduction reaction (eNRR) under ambient conditions. Using high-throughput screening and first-principles calculations based on the density functional theory (DFT) method, three eNRR catalyst candidates, i.e. Mo-Por, Tc-Por, and Nb-Por, were screened out, with the eNRR onset potentials on them being −0.36, −0.53, and −0.74 V, respectively. Furthermore, these catalyst candidates all have good stability and selectivity. Analyzing the band structures found that these catalyst candidates all are metallic, which is needed for good electrocatalysts. Ab initio molecular dynamics (AIMD) simulations show that these catalyst candidates have good stability at 500 K. It is hoped that our work will open up new possibilities for the experimental synthesis of electrochemical ammonia catalysts.