fig4

Figure 4. (A) Scheme of the formation of Ni SAs/N-C^[31]. Copyright 2023, ACS Publications; (B) Schematic Illustration for Construction of Fe₁-Ni₁-N-C with Neighboring Fe and Ni Single-Atoms Based on ZIF-8^[32]. Copyright 2023, ACS Publications; (C) Schematic illustration of synthetic route of Pd₁@ZrO₂^[33]. Copyright 2023, ACS Publications; (D) Schematic illustration showing Ni²⁺ decoration in UiO-66-NH₂ via an efficient microwave-assisted method and the subsequent coordination environment modulation of single Ni Atoms to afford Ni₁-X/MOF^[34]. Copyright 2023, ACS Publications; (E) Schematic illustration showing the synthesis of Al-TCPP-Pt for photocatalytic hydrogen production^[35]. Copyright 2023, Wiley. SAs: Single atoms; ZIF: zeolitic imidazolate framework; MOF: metal-organic framework.