Photoelectrochemical behavior of a rhodamine dye intercalated in a photocatalytically active layered niobate and photochemically inert clay

Abstract

We investigated photoelectrochemical behavior of rhodamine 6G (R6G) dye intercalated in layered oxides of semiconducting hexaniobate and photochemically inert saponite clay. The R6G-clay intercalation compound generated comparable cathodic and anodic photocurrents. Photocurrent action spectra indicated that both the photocurrents were ascribed to photoexcitation of R6G monomers and dimers present in the interlayer spaces. On the other hand, the R6G-niobate intercalation compound exhibited a relatively large cathodic and small anodic photocurrents. Action spectra of the R6G-niobate system indicated that the photocurrents were generated by photoexcitation of only the R6G monomers while that the coexisting dimeric species were apparently silent. This result was explained by that the photocurrents were generated through photosensitization of the photocatalytically active semiconducting niobate layers with electron transfer from the photoexcited R6G monomers, whereas that the dimers were deactivated through dye-dye interactions.