Lanthanide-titanium-oxalate clusters and their degradation products, photocurrent response and photocatalytic behavioursElectronic supplementary information (ESI) available. CCDC 1828904 and 1828905 contain the supplementary crystallographic data for 1 and 2, respectively. Structures of 2 and 3, IR and UV-vis spectra of 1′-3′, crystal data and structural refinement parameters. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c8nj02247j

Incorporation of lanthanide ions (Ln) into TiO 2 nanomaterials has recently been proved to be an efficient strategy to explore photoelectric active materials. Herein, three lanthanide-titanium oxo-clusters (LnTOCs), formulated as [Ln 2 Ti 6 O 2 (C 2 O 4 ) 4 (NO 3 ) 2 (O i Pr) 20 ]·2HO i Pr (Ln = La ( 1 ), Ce ( 2 ) and Eu ( 3 )), are reported. Their structures feature two Ti 3 O 13 subunits and a central La 2 O 14 subunit bridged by four oxalate ions. The cluster core is surrounded by 20 O i Pr groups, which easily undergo dealkoxy reactions. TOCs have now been used as photocatalytic materials under ambient conditions, and in most cases they should already not be the original clusters due to their sensitivity to moisture. However, less work on the degradation clusters has been discussed. In this work, the degradation products were carefully characterized and polymeric Ln-TiO-C 2 O 4 materials were obtained. Using such materials, photocurrent response and photocatalytic dye degradation were examined. The improvements in the photocurrent intensity and photocatalytic activity of dye-degradation are attributed to the cooperative effects of lanthanide and oxalate doping in TiO catalysis. Three Ln-TiO-C 2 O 4 polymers were obtained spontaneously from their titanium oxo-clusters and the advantages of doped TiO materials were discussed based on the experiments of photocurrent conversion and photocatalytic dye degradation.