Heterometallic lead-iodocuprate hybrids with transition-metal complexes: syntheses, structures, photoelectricity and photocatalysis

Abstract

Heterometallic lead-iodocuprate hybrids [TM(en)₃]PbCuI₅ (TM = Mn (1), Fe (2), Ni (3); en = ethylenediamine) were prepared using transition-metal complex cations formed in situ as structure-directing agents under solvothermal conditions. In compounds 1–3, the PbI₆ PBUs are joined by edge-sharing forming a [PbI₄]_n chain, and the [PbI₄]_n chain is capped by the CuI₄ PBUs to form 1-D hetero lead-iodocuprate [PbCuI₅]_n²ⁿ⁻ chains. Compounds 1–3 exhibited rapid, reproducible and durable photocurrent responses with current densities of 5.15, 3.73, and 1.74 μA cm⁻², respectively, under Xe light irradiation. They showed effective photocatalytic activities for the degradation of crystal violet (CV), with degradation ratios in the range of 79.8–93.2% after light irradiation for 140 min. Compounds 1 and 2 exhibited higher photocatalytic activities, which is attributed to their higher photocurrent intensities. An investigation of the photocatalytic mechanism revealed that ˙O₂⁻ radicals were the dominant reactive species in the photodegradation of CV, whereas the h⁺ holes and ˙OH radicals played synergistic roles during the photodegradation.