Syntheses, structures, photoelectric properties and photocatalysis of iodobismuthate hybrids with lanthanide complex cations

New iodobismuthate hybrids with lanthanide complex counter cations, [Ln(DMF)(8)][Bi2I9] (Ln = La (1), Eu (2)) and [Tb(DMF)(8)](2)[Bi2I9](2) (3) (DMF = N,N-dimethylformamide), were prepared using solvated Ln(iii) complexes formed in situ as structure-directing agents. The dimeric [Bi2I9](3-) anion moieties of compounds 1-3 are aggregated by two slightly twisted BiI6 octahedra through face-sharing mode. The different crystal structures of 1-3 are due to the different vertical bar center dot center dot center dot vertical bar and C-H center dot center dot center dot I hydrogen bond interactions. Compounds 1-3 have narrow semiconducting band gaps at 2.23, 1.91 and 1.94 eV, respectively. Under Xe light irradiation, they exhibit steady photocurrent densities that are 1.81, 2.10 and 2.18 times higher than that of pure BiI3, respectively. Compounds 2 and 3 exhibited higher catalytic activities than 1 in the photodegradation of organic dyes CV and RhB, which are attributed to the stronger photocurrent response derived from the redox cycles of Eu3+/Eu2+ and Tb4+/Tb3+.

Automated summary

New iodobismuthate hybrids with lanthanide complex cations were synthesized, and their crystal structures, band gaps and photocurrent densities were investigated. The compounds exhibited narrow semiconducting band gaps and higher photocurrent densities compared to pure BiI3. Compounds with Eu and Tb cations showed higher catalytic activities in the photodegradation of organic dyes, attributed to the stronger photocurrent response derived from redox cycles of Eu3+/Eu2+ and Tb4+/Tb3+.