Photocatalytic electron flow through the interface of titania nanosheets and mesoporous silica hybrid films

Photoinduced Electron Transfer between the Anionic Porphyrins and Viologens in Titania Nanosheets and Monodisperse Mesoporous Silica Hybrid Films

“…UV irradiation of the (TNS)/(H 2 TCPP 4− -AMMSS) films induced the oxidative consumption of the H 2 TCPP 4− molecules. These behaviors were quite similar to those of the other TNS/MPS hybrid systems containing a cationic MTMPyP 4+ . − , The photochemical behavior in the present organic and inorganic hybrid films can be applied in unique photofunctional devices such as capacitors, triggers for chemical reactions, artificial Z-schemes, or applications for solar energy storage.…”

“…The hybridization of nanostructured inorganic hosts with organic photofunctional molecules has been widely and extensively studied. − The photofunctional organic functional molecules hybridized with nanosized inorganic hosts have been observed to have unique redox properties in photochemical and photophysical processes. ,− In our previous studies, − consecutively stacked hybrid thin films of mesoporous silica films ( cubic -MPS) − or monodisperse mesoporous silica spheres (MMSS) − and layered titania nanosheets (TNS) ,,− were shown to exhibit unique photoinduced electron transfer between the cationic porphyrins (MTMPyP 4+ ; M = H 2 , Zn, and Co) and methyl viologen (MV 2+ ), which were separated and were present in different inorganic hosts. , Upon UV-light illumination of the photocatalytic TNS, , the (MV 2+ -TNS)/(H 2 TMPyP 4+ -MMSS), MV 2+ radical ions (MV +• ) were formed at the expense of the oxidative consumption of H 2 TMPyP 4+ , resulting in electron transfer through the interface between the TNS and mesoporous silica, thus leading to charge separation at the interface between the two nanostructured inorganic hosts. ,, The charge separated states obtained in these materials were highly stabilized and lasted for several hours even in the ambient atmosphere …”

“…It can reasonably be assumed that the oxidation of H 2 TCPP 4− molecules in AMMSS can be coupled with the reduction of MV 2+ molecules in the TNS layers. During this process, e − cb and/or h + can migrate through the TNS/AMMSS interface. , …”

“…During this process, e À cb and/or h þ can migrate through the TNS/AMMSS interface. 29,34 To obtain evidence for the simultaneous occurrence of the oxidation of H 2 TCPP 4À molecules within the AMMSS cavities and the reduction of MV 2þ within the TNS interlayers, i.e., to determine whether the electron (and/or hole) migration through the TNS/AMMSS interface takes place, poly(styrene) (PS) film was placed between the (MV 2þ -TNS) and the (H 2 TCPP 4À -AMMSS) component films as an electrically insulating third layer. 28,30 Figure 1b shows films containing the inserted PS layer, i.e., (MV 2þ -TNS)/PS/(H 2 TCPP 4À -AMMSS) films, and Figure 3 shows their absorption spectra following UV irradiation.…”

Unique Solvatochromism of a Membrane Composed of a Cationic Porphyrin−Clay Complex

“…The structural formula for SSA is [(Si 7.20 Al 0.80 )(Mg 5.97 Al 0.03 )O 20 (OH) 4 ] −0.77 (Na 0.49 Mg 0.14 ) +0.77 . Since the synthetic clay mineral is pure, colorless, and well characterized, its application to the inorganic/organic hybrid materials attracts much attention, especially from the viewpoint of photochemistry. − The typical transparent clay mineral−porphyrin membrane was prepared as follows. The aqueous colloidal solution of SSA (1.0 g L −1 , 150 μL) and cis -DPyP (1.0 × 10 −4 M in water, 37.5 μL (5.0% vs CEC (cation exchange capacity) of the clay)) was added to water (3 mL) with stirring.…”