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.