Fabrication of Cu(I) Coordination Polymers with Open Metal Sites for Enhanced Photocatalytic Activity

Coordination polymers (CPs), rich in open metal sites, have extensive applications in the catalysis field. Herein, two Cu(I) coordination polymers, {[Cu(3-bcda)Cl]·H₂O}_n (Cu-BCD) and {[Cu₂(3-padpe)₂Cl₂]·H₂O}_n (Cu-PAD), were synthesized using Cu as the central metal, N,N'-bis(pyridin-3-yl)cyclohexane-1,4-dicarboxamide (3-bcda) and 4,4'-bis(3-pyridylformamide)diphenylether (3-padpe) as linkers, for the photocatalytic degradation of oxytetracycline (OTC) and Cr(VI) reduction. Compared with Cu-BCD, Cu-PAD had more open metal sites, and its conjugated ligand structure was more conducive to electron transfer, reducing the complexation of charge carriers, which exhibited excellent photocatalytic performance. The photocatalytic degradation efficiency of Cu-PAD for OTC reached 85.34%, and the reduction efficiency for Cr(VI) was 85.04%. The toxicity analysis of the OTC degradation products indicated that the degradation solution was nontoxic. The density functional theory (DFT) results indicated that the metal coordination sites acted as electron donors and the ligand units acted as electron acceptors, effectively participating in redox reactions. It is worth noting that Cu-PAD displayed great photocatalytic performance in actual water and soil. Overall, Cu-PAD is supposed to become a highly efficient photocatalyst for environmental remediation.