The free energetics and Fe–C coordination for the most favorable CO dissociation channels on six surfaces, all on A-P5 sitesa.
| Surface | G a(TS1) (eV) | G a(TS2) (eV) | G a(TS3) (eV) | CN(A-P5) | ΔCN |
|---|---|---|---|---|---|
| Fe2C(111) | 0.88 | 0.78 | 2.06 | 2.06 | 0.09 |
| Fe7C3(071) | 0.86 | 1.04 | 1.24 | 1.55 | −0.15 |
| Fe5C2(510) | 0.88 | 0.98 | 1.31 | 1.59 | −0.14 |
| Fe5C2(021) | 0.70 | 1.14 | 1.14 | 1.44 | −0.21 |
| Fe3C(031) | 0.90 | 1.16 | 1.11 | 1.47 | −0.13 |
| Fe3C(102) | 0.83 | 1.40 | 1.44 | 1.41 | −0.33 |
a
The listed data include the effective free energy barriers of C hydrogenation to CH, CH diffusion and CO dissociation (corresponding to TS1, TS2 and TS3 in Fig. 4b), the average Fe–C coordination number of five Fe atoms in the A-P5 site (CN(A-P5)) and the change of CN for the Fe atoms at the A-P5 site coordinated with CH before and after its diffusion (ΔCN).