N 2 reduction to NH 3 on surfaces of Co-Al 18 P 18 , Ni-Al 21 N 21 , Fe-B 24 N 24 , Mn-B 27 P 27 , Ti-C 60 and Cu-Si 72 catalysts

The abilities of Co-Al P , Ni-Al N , Fe-B N , Mn-B P , Ti-C and Cu-Si as catalysts for N -RR to create the NH are investigated by theoretical levels. The ∆E and ∆E of Co-Al P , Ni-Al N , Fe-B N , Mn-B P , Ti-C and Cu-Si are investigated. The ∆E of N -RR intermediates and ΔG of reaction steps of N -RR on Co-Al P , Ni-Al N , Fe-B N , Mn-B P , Ti-C and Cu-Si are examined. In acceptable mechanisms, the *NN → *NNH step is potential limiting step and *NN → *NNH step in enzymatic mechanism is endothermic reaction. The ∆G of *NHNH2 → *NH NH step on Co-Al P , Ni-Al N , Fe-B N , Mn-B P , Ti-C and Cu-Si are -0.904, -0.928, -0.860, -0.882, -0.817 and -0.838 eV, respectively. The Co-Al P and Ni-Al N have the highest ∆G values for reaction steps of N -RR. Finally, it can be concluded that the Co-Al P , Ni-Al N , Fe-B N and Mn-B P have acceptable potential for N -RR by acceptable pathways. The structures of Co-Al P , Ni-Al N , Fe-B N , Mn-B P , Ti-C and Cu-Si and N -RR intermediates are optimized by PW91PW91/6-311+G (2d, 2p) and M06-2X/cc-pVQZ as theoretical levels in GAMESS software. The convergence for force set displacement of Co-Al P , Ni-Al N , Fe-B N , Mn-B P , Ti-C and Cu-Si and N -RR intermediates are 1.5 × 10 Hartree/Bohr and 6.0 × 10 Angstrom. The Opt = Tight and MaxStep = 30 are considered to optimize Co-Al P , Ni-Al N , Fe-B N , Mn-B P , Ti-C and Cu-Si and N -RR intermediates. The frequencies of Co-Al P , Ni-Al N , Fe-B N , Mn-B P , Ti-C and Cu-Si and N -RR intermediates are calculated.