fig4

Figure 4. DFT-based analysis of the catalytic mechanism. (A) Top views of M4Zn-S and M4-S; PDOS of (B) Fe and (C) Ni for M4Zn-S and M4-S; (D) Bader charge analysis of different elements for M4Zn-S and M4-S; Bader charge map of Fe and Ni in (E) M4Zn-S and (F) M4-S; (G) Free-energy diagrams of OPM for M4Zn-S and LOM for M4-S. PDOS: Projected density of states; DFT: density functional theory; OPM: oxide pathway mechanism; LOM: attice oxygen-mediated mechanism.