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Fe 3 O 4 –TiO 2 core-shell nanocomposites were successfully prepared and characterized by FE-SEM, XRD, UV–vis absorbance spectra, and EDX. The FE-SEM and EDX studies revealed core-shell structure with a particle size of ca. 40–50 nm. We adopted HeLa cells as a model to investigate the thermal-photocatalytic cell killing efficiency of Fe 3 O 4 –TiO 2 using 150 μg/mL dose content for 10 min exposure time. We found neither only AC magnetic-field induction nor only photoirradiation condition could kill the cancer cells up to satisfactory level using Fe 3 O 4 –TiO 2 nanocomposites. Finally, the results revealed that almost 100% cancer cells were destructed by Fe 3 O 4 –TiO 2 nanocomposites whereas for bare Fe 3 O 4 and bare TiO 2 , 90% and 56% cancer cells were killed, respectively, under combined AC (alternating current) magnetic-field induction and UV–vis photoirradiated conditions.

In this article, we have reported self-assembled synthesis of pore tunable, mesoporous ZnS microsphere and its photocatalytic activity. The photocatalytic activity was evaluated using Methyl Orange (MO) as model pollutant under UV light irradiation. The mesoporous photocatalysts was synthesized using hydrothermal method without using any templates or catalysts in large scale. The products were characterized by field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD) and energy-dispersive X-ray spectrometry (EDX). The nitrogen adsorption analysis confirmed the presence of mesoporous structure. The pore size of the photocatalysts could be enlarged from 2.6 to 7.2 nm by changing the concentration of the zinc precursor. The microsphere formation has been facilitated by self-assembly followed by Ostwald ripening process. In conclusion, this simple synthetic methodology open new vistas to prepare mesoporous photocatalysts in large scale.

Without using an external precursor a simple and one-step method for the synthesis of C-doped TiO 2 submicrospheres has been developed via hydrolysis of titanium tetraisopropoxide in pure methanol followed by calcination under air at 500 °C. Also, with the addition of d -glucose and NH 4 OH solution during the hydrolysis process, C- or N-doped and C, N co-doped TiO 2 submicrospheres can be prepared by the same method. The size of the submicrosphere was homogeneous ranging from 300 to 400 nm. The resulting submicrospheres were characterized by FE-SEM, TEM, XRD, XPS and UV–vis diffuse reflectance spectroscopy. The C- or N-doped and C, N co-doped submicrospheres showed obvious absorption in the wavelength up to around 650, 500 and 650 nm, respectively. The activity of the photocatalysts was evaluated by the hydroxyl radical formation under visible light irradiation. Finally, the mechanism of sphere formation is discussed.

The bilayer thin film composed of graphite silica (GS) and TiO 2 was prepared by the laser ablation technique. The properties of the thin films considerably depended on the laser ablation conditions such as gas pressure and substrate temperature in a chamber. The laser ablation of GS caused complete disappearance of the quartz XRD (X-ray diffraction) peaks in GS. The GS loading, especially at a thickness of around 200 nm, led to significant enhancement in the photocatalytic activity of the TiO 2 thin film for the hydrogen production and the methylene blue decomposition in spite of the destruction of the quartz crystal in GS.

N-doped TiO2 thin films were prepared by the laser ablation method under an N2 gas atmosphere. Properties of the films such as color, the relative amount of N doped and the crystal structure strongly depended on substrate temperature and N2 gas pressure. XPS data indicated that the amount of doped N unexpectedly increases with decreasing N2 gas pressure in the range of ca. 40–270 Pa. We proposed that the N-doping occurred when N species and TiO2 particles collide on the substrate. The decomposition of methylene blue using the N-doped TiO2 thin film was also performed under visible light irradiation.

The effect of carbon nanotubes on TiO2, for the photocatalytic H2 gas production from water/alcohol mixtures, was investigated. The drastic synergy effect was found with an increase in the amount of H2 gas by a factor of ca. 400 simply by mixing single walled carbon nanotubes (SWNTs) with TiO2. A comparison between SWNTs/TiO2 and Pt/TiO2 mixtures was made for the amount of H2 gas produced. Based on the observed results, a plausible mechanism was proposed.

Photocatalytic hydrogen production from methanol aqueous solution containing mixture of titanium dioxide (TiO 2 ) and graphite silica (GS) was enhanced by laser ablation in liquid. It was found that the amount of hydrogen gas evolved in lased GS–TiO 2 was less than that in raw GS–TiO 2 mixture. However, the amount of hydrogen gas with the mixture of raw TiO 2 and lased GS was two times as large as that of the raw GS–TiO 2 mixture. This enhancement effect may be attributed to increase in the reaction surface area by the fine-subdivided GS particles and the aggregation of lased GS and raw TiO 2 .

The photocatalytic production of hydrogen gas from aqueous methanol solution was performed using powdered mixtures of graphite silica (GS) and platinized TiO 2 (Pt/TiO 2 ) or those of GS, Pt and TiO 2 . The addition of GS to Pt/TiO 2 resulted in the decrease of the amount of H 2 gas, whereas the addition of GS to mixtures of TiO 2 and Pt led to the incremental production of H 2 gas. This effect is attributed to the aggregation of GS, TiO 2 and Pt in suspension. The new additional electron transfer process of TiO 2 → Pt → GS caused the increment of the amount of hydrogen gas.

Hydrogen production was performed under visible-light and combined UV/visible-light irradiation by using a system consisting of cobalt(II)tetraphenylporphyrin (CoTPP), methylviologen (MV2+), ethylenediaminetetraacetic acid disodium salt and Pt-loaded poly( l -glutamate) (Poly(Glu)) in aqueous decylammonium chloride (DeAC) solution. CoTPP was solubilized in hydrophobic clusters of DeAC induced by its cooperative binding to Poly(Glu). About 0.15 and 3.5 μmol of hydrogen gas were obtained after irradiation for 3 h using visible-light and combined UV/visible-light, respectively. The rate of hydrogen evolution depended on the change in the conformation of Poly(Glu) induced by the cooperative binding with DeAC. An electron was transferred from CoTPP to MV2+ in the Poly(Glu)–DeAC complex system via the singlet state, finally resulting in the hydrogen evolution.

The photocatalytic production of hydrogen gas from water–methanol mixtures was performed in contact with a suspended mixture of powdered titanium dioxide (TiO2) and graphite silica (GS), a naturally available mineral. A drastic synergy effect for hydrogen production was found for GS in collaboration with TiO2. The amount of hydrogen gas evolved from water–methanol mixtures was increased by a factor of ca. 100 simply by mixing GS with TiO2. The synergy effect is attributed to the enrichment of hydrogen ions in the clay components of GS and aggregation of GS and TiO2 particles.

Hydrogen production was performed under visible light irradiation by using a system consisting of cobalt(II)tetraphenylporphyrin, methylviologen, ethylenediaminetetraacetic acid disodium salt and Pt-loaded poly( l -glutamate) (Poly(Glu)) in aqueous decylammonium chloride (DeAC) solution. The rate of hydrogen evolution depended on the change in the conformation of Poly(Glu) induced by the cooperative binding with DeAC.

Rose-type magnetic nanoplates (RTMNPs) were synthesized by a simple hydrothermal decomposition method where FeCl 2 ·4H 2 O was solely used as a precursor. The synthesized nanoplates were characterized using XRD, FE-SEM, UV–vis absorption (reflectance) spectra and magnetic hysteresis loops. The resulting nanoplates were in the ranges of size 350–500 nm and width 60–70 nm with high crystallinity, purity (shown by XRD) and reproducibility. These iron oxide nanoplates have a great potential in magnetic nanodevices and biomagnetic applications.

Copper nanoparticles were successfully synthesized by the borohydride reduction of copper nitrate salt in water/CH 3 CN mixed solvent under inert argon-purged conditions. Cu nanoparticles were synthesized in large-scale production for the first time by introducing CH 3 CN into water and preventing oxidation during the preparation of nanoparticles. Nanoparticles were characterized by using UV–visible absorption spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) techniques. High resolution TEM pictures showed the formation of homogeneous cubic-structured copper nanoparticles with sizes less than 100 nm. This new kind of synthesis method shows the excellent stability compared with that of citrate-protected copper nanoparticles, which may provide an efficient way to improve the fine tuning of the structure and size of copper nanoparticles.

Spectroscopic and potentiometric studies of chlorophyll a (Chl)-copolypeptide of L-ornithine and L-tyrosine (poly (L-Orn, L-Tyr)) complexes in an aqueous surfactant solution indicate that Chl molecules are incorporated into poly (L-Orn, L-Tyr)-surfactant complexes accompanying a conformational change from a random coil to α-helix and a conformation-dependent energy transfer effectively occurs from the L-tyrosine residue to Chl in the Chl-copolypeptide-surfactant system.

Pyrene was adsorbed to a TiO 2 surface from water–alcohol mixture solutions at 25 °C and pyrene–TiO 2 particles were recovered by filtration. We found that the surface of TiO 2 thus recovered is relatively hydrophobic and pyrene is not decomposed but keep its fluorescence characteristics on the spectral measurement under ultraviolet excitation.

The association constants of pyrene inclusion complexes with β-cyclodextrin and methylated β-cyclodextrins were determined using equations which provide an accurate description of the variation in the vibronic-band-intensity ratio of pyrene monomer fluorescence in the presence of cyclodextrins.

The mechanism of enhancement in the energy transfer between rhodamine 6G and 3,3'-diethylthiacarbocyanine iodide by sodium lauryl sulfate in the premicellar region was studied by a picosecond laser technique. The Forster mechanism with an increased local concentration suggesting dye-rich induced micelle formation was concluded from the shape of the decay curve.

The energy transfer between rhodamine-6G and 3,3′-diethylthiacarbocyanine iodide was studied in aqueous solutions of sodium lauryl sulfate. A highly enhanced energy transfer was observed at very low dye concentrations in the premicellar region. This effect can be explained in terms of the formation of dye-rich mixed micelles.

The resonance Raman spectra of chlorophyll a (Chl)-N-methylmyristamide (NMMA) in aqueous surfactant solutions indicates that both the carbonyl group at the 9-position and the central Mg atom of Chl interact with NMMA. The 1215 cm −1 Raman band was found to be sensitive to the formation of premicellar aggregates induced by the hydrophobic solutes (Chl and NMMA).

The system pyrene-cyclodextrin-sodium dodecyl sulfate (SDS) in aqueous solution was studied as a function of the concentration of SDS. The behavior of absorption and fluorescence spectra of pyrene is explained in terms of complex formation with β-cyclodextrin and SDS below the critical micelle concentration and the formation of mixed micelles containing α- or β-cyclodextrin above it.

The laser and fluorescence behavior was studied for the mixed dye system containing various concentrations of 3,3′-diethylthiacarbocyanine iodide and rhodamine 6G. A new way of confirming the occurrence of energy transfer is presented on the basis of the reabsorption effect.