Visible light photoelectrochemical activity of K{sub 4}Nb{sub 6}O{sub 17} intercalated with photoactive complexes by electrostatic self-assembly deposition

Electrostatic self-assembly deposition (ESD) results in the intercalation of Ru(bpy){sub 3} {sup 2+} or methylene blue (MB) into the niobate layered oxide right after the cations come into contact with [Nb{sub 6}O{sub 17}]{sup 4-} nanosheets. Monolayers can be obtained by the exfoliation of proton exchanged K{sub 4}Nb{sub 6}O{sub 17} (KNbO) in an aqueous tetrabutylammonium (TBA) solution as revealed by the atomic force microscopy micrographs. UV-vis spectra show that intercalated films are able to absorb in the visible light range. Heat-treatment of Ru(bpy){sub 3} {sup 2+} resulted in the red-shift in the absorption spectra, which was assigned to the enhancement in the interaction between the complex molecules and [Nb{sub 6}O{sub 17}]{sup 4-} host layer. Intercalated niobate layered oxides are able to produce photocurrent as a result of the electron transfer from the excited guest molecule to the host layer under visible light illumination. Ru(bpy){sub 3} {sup 2+} intercalated niobate layered oxide shows photocatalytic activity under visible light illumination to produce H{sub 2} from water-methanol solution. -- Graphical abstract: Charge transfer mechanism in the interlayer of the layered oxide.