Visible light photoelectrochemical activity of K4Nb6O17 intercalated with photoactive complexes by electrostatic self-assembly deposition

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

“…14), 18) We assume a similar mechanism for the R6G-niobate system, and Fig. 8 This is rationalized by that the redox potential of R6G * , reported to be -1.78 V vs Ag/AgCl, 40) allows electron injection into the conduction band of hexaniobate (-0.96 V vs Ag/AgCl).…”

“…However, we may observe photochemical communications in the R6G-niobate intercalation compound under appropriate conditions, because photoinduced electronic/energetic interactions should be allowed between the niobate layers and the R6G molecules if we consider previous studies of niobate-dye systems. 17), 18) Since the R6G molecules exhibit peculiar aggregative behavior in the interlayer spaces of niobate, 35) the photochemical host-guest interactions may be related to the aggregated state of the intercalated dye species.…”

“…14)- 19) In fact, the layered niobates and titanates intercalated with a ruthenium complex 14),15),17), 18) and porphyrin 19) have been utilized as photoelectrodes by which photoenergy of visible light is converted to electric current. However, variety of the dyes examined as photosensitizers of layered niobates and titanates has been rather limited compared with sensitization of TiO2 that has vastly been investigated as a typical wide band-gap semiconductor possessing nonporous three dimensional structure.…”

Chemical modification of niobium layered oxide by tetraalkylammonium intercalation

“…14 Chemical modification of niobate by the intercalation route is mainly driven by the fact that the pre-intercalation with polyether monoamine surfactant, 15 tetraalkylammonium ion (from tetrabutylammonium hydroxide solutions), 16 and n-alkylammonium ion 17 promotes the exfoliation of layered niobate. This process produces a colloidal dispersion of inorganic nanosheets, suitable for preparation of thin films to generate photocurrent using [Ru(bpy) 3 ] 2+ sensitizer, 18 photoluminescence from rare earth ions, 19 molecular hydrogen from water under illumination, 20 protonic conductor, 21 Li + conductor, 22 interstratified materials with layered double hydroxides, 23 acid catalysts, 24 macroporous niobate, 25 biosensors based on hemoglobin 26 and other materials, as reviewed recently. 27 In addition, niobate nanosheets in colloidal dispersion can undergo a curling process forming tubular or scrolled inorganic nanoparticles under soft chemical conditions.…”

Electrochemical behavior of Ag+ intercalated layered oxides

“…As a photocatalysis in water splitting process, interlayer of layered oxides acts as a site for the oxidation of water by holes produced in the semiconductive host nanosheet layer under band gap illumination [15][16][17][18]. Recently, some interesting electrochemical properties of Ti and Nb layered oxides such as n-type semiconducting behavior of the host nanosheet layer with photoelectrochemical response [4,5], clear electrochemical redox reaction of the Ag + /Ag couple and visible light response of the RuðbpyÞ 2þ 3 in the interlayer to yield a significant amount of photocurrent [6,19] have been revealed in our laboratory. These electrochemical reactions are based on the unique two-dimensional structure of these types of layered oxides in principle.…”