4. Conclusion
In conclusion, for the proposed ’atomic diversity free but intrinsic properties variety’ homonuclear TM catalyst, we verified that the ’capture-charge distribution-recapture-charge redistribution’ mechanism could occur in dual TM catalyst for both end on and side on N2 configuration under the synergistic effect of dual TM sites as well. After ensuring the stability of TM-anchored defective C3N systems, the heteronuclear of homonuclear DAC behavior is revealed by comparing the bond length (TM atom bonded with an adjacent atom), charge transfer, magnetic moment, d band center of TM1 and TM2. Subsequently, we highlighted the advantages of heteronuclear DAC. We made high throughput screenings to filtrate initial candidates for eNRR, and the corresponding screenings are the adsorption Gibbs free energy of N2(ΔG*N2 < 0 eV), the first (ΔG*N2-ΔG*N2H < 0.50 eV) and last pronation steps (ΔG*NH2-ΔG*NH3< 0.50 eV). Meanwhile, machine learning is implemented to verify the impact of the atomic diversity effect. However, it is entirely removed, and it is suggested the rTM may take an essential role in the NRR process, which should be further studied in the future.
Consequently, seven candidates, Mn2@site1, Ru2@site1, Co2@site2, W2@site2, Os2@site3, V2@site4, and Cr2@site4 are selected for fully eNRR calculation, and their corresponding limiting potentials are -0.45 V, -0.36 V, -0.44 V, -0.25 V, -0.48 V, -0.28 V, and -0.29 vs CHE, respectively. To evaluate the intrinsic mechanism, the electronic properties, including pDOS, Bader analysis, charge density difference, and COHP, are implemented for the intrinsic properties only determined systems; it was found that each TM atom exhibits different roles in the eNRR process, which lower the energy barriers for each intermediate since the synergistic effect between two TM active sites under the proposed ’capture-charge distribution-recapture-charge redistribution’ mechanism. Finally, the selectivity and thermostability are systematically investigated by comparing the adsorption Gibbs free energy of *N2 and *H, as well as the AIMD simulations, and five candidates, Mn2@site1, Co2@site2, Os2@site3, V2@site4, and Cr2@site4 are filtrate eventually. This study proves that the homonuclear DAC can be functionalized as a heteronuclear DAC and develops a new method for simplifying the complicated secondary experimental heteronuclear DAC synthesis procedure.