Donor-acceptor covalent organic frameworks of nickel(II) porphyrin for selective and efficient CO2 reduction into CO

Donor-acceptor two-dimensional covalent organic frameworks, PD-COF-23 and PD-COF-23-Ni, are constructed and applied for selective CO2 reduction with CO conversion rates of 20.9 mu mol g(-1) h(-1) and 40.0 mu mol g(-1) h(-1), respectively, in the absence of any additional photosensitizers and noble metal co-catalysts within an operation time of 25 h. The multilayer nanosheet structure, efficient charge separation and transport, and internal reductive quenching cycle of the NiTAPP fragments of PD-COF-23-Ni result in its higher photocatalytic efficiency than that of PD-COF-23.