fig4

Figure 4. Synthesis route of PC-COF. (i) o-DCB:Ethanol = 9/1 (v/v), HAc (6 M), 120 °C and 7 days. TAPB: 1,3,5-tris(4-aminophenyl) benzene; BFBP2+: 1,1-bis(4-formylphenyl)-4,4′-bipyridinium; COF: covalent organic framework; DCB: dichlorobenzene.