fig2

Figure 2. (A) Schematic crystal structure of SFM (plotted by the authors); (B) Schematic diagram of the crystal structure of ideal double perovskite SFM and crystal structure after introducing ADs. Reproduced with permission^[32], Copyright 2018, Wiley-VCH; (C) HRTEM image of (220) lattice fringes and corresponding fast Fourier transform. Reproduced with permission^[49], Copyright 2021, Wiley-VCH; (D) Oxygen vacancy formation energy for different B−O−B’ bonds in SFM. Reproduced with permission^[41], Copyright 2011, Royal Society of Chemistry; (E) Mössbauer spectra of SFM prepared by (a) sol-gel method and (b) solid-state reaction method; (F) Scanning electron microscope diagram of SFM powder prepared by sol-gel method; (G) SEM diagram of SFM powder prepared by solid-state reaction method; (H) HRTEM diagram of SFM prepared by sol-gel method. Reproduced with permission^[20], Copyright 2014, Elsevier; (I) Schematic diagram of the reaction of SFM@CF-SDC solid oxide fuel cell anode under hydrogen. Reproduced with permission^[67], Copyright 2020, Elsevier; (J) Schematic diagram of solid oxide electrolysis cell cathode electrolysis under CO₂ atmosphere. Reproduced with permission^[96], Copyright 2022, American Chemical Society. SFMO: Sr₂FeMoO₆; CF: Co-Fe nanoparticles; RP-SFM: Ruddlesden-Popper phase Sr₃FeMoO₇; SDC: Sm doped ceria; LSGM: La_0.2Sr_0.8Ga_0.8Mg_0.2O₃; SFM: Sr₂FeMoO₆; ADs: anti-site defects; SEM: scanning electron microscope.