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This study examined the photoelectric conversion efficiency of the dye-sensitized solar cell (DSSC) when the surface of a nanometer-sized TiO 2 film, which was prepared using the solvothermal method, was modified by five acid compounds. The TiO 2 film exhibited an anatase structure with an average particle size in the range of 10-15 nm, and the maximum absorption band was shown in the UV-visible spectrum around 360 nm. The surface colors of the carboxylic acid-modified TiO 2 films were changed to light or dark with differing energy conversion efficiencies. Particularly, the conversion efficiency was considerably enhanced from approximately 6.25% for the non-modified TiO 2 film to approximately 7.50% for the film treated by acetic acid of 1.0 mole, with the N719 dye under 100 mW/cm 2 of simulated sunlight. FT-IR analysis of the films after N719 dye adsorption confirmed that the IR spectrum of the modified TiO 2 showed a sharp and strong band at 500 cm −1 , which was assigned to a metal-O bond, due to the formation of a new Ti-O bond between the O of COO − and the Ti atom, which was relatively weaker in the non-modified TiO 2 . Furthermore, these results were in agreement with an electrostatic force microscopy (EFM) study showing that the electrons were transferred rapidly to the surface of the acetic acid-modified TiO 2 film, compared with that on the nonmodified TiO 2 film.

To improve the ortho-or para-xylene selectivity via the isomerization of meta-xylene, the acid sites located on the external surface of zeolite Y crystals were neutralized by using the intrinsic mechanochemical method, which resulted in reduced coke formation. Zeolite Y crystals were mixed in an agate mortar with alkaline earth metal oxides supported on micro spherical non-porous silica. The catalytic performances into o-or p-xylene from the m-xylene isomerization reaction were enhanced, especially with either the CaO-or MgO-neutralized catalyst, as verified by adsorption of bipyridine, which could not access the pore channel due to its bulky molecular size. These consistent changes in the reaction performance could be ascribed to the decrease in the number of acid sites on the external surfaces.

This study investigated the decomposition activities of toluene on 10 mol% Al-W-incorporated mesoporous titano (15 mol %) silicates. The mesopore sizes observed in the transmission electron microscopy images ranged from 2.0 to 5.0 nm, and the pores were irregular on the addition of 10 mol% Al or W ions, but changed to regular hexagonal forms with the simultaneous additions of Al and W. The X-ray photon spectroscopy results showed a shift of the special peak for Ti2p in Al-incorporated mesoporous titanosilicates to a stronger binding energy compared to those of mesoporous titanosilicates and Al-incorporated mesoporous titanosilicates. Three O1s peaks in the spectra of the Al and W coexisted samples were observed at 530.5 and 531.7, 533, and 533.7eV, which were assigned to Ti-Os in TiO2 and Ti2O3, Si-O in SiO2 and Al-O in Al2O3, respectively. The toluene molecules desorbed at lower temperatures over W-incorporated mesoporous titanosilicates, and the amounts of toluene desorbed were also small; however, Al-incorporated mesoporous titanosilicates adsorbed much more toluene, particular over Al7.5-W2.5-Ti15-Si75. The photocatalytic decomposition of toluene was more enhanced over Al7.5-W2.5-Ti15-Si75 than over Al-or W-incorporated mesoporous titanosilicates only.

This study investigates the photocatalytic performance of V-TiO 2 for removal of highly concentrated ammonia (1,000 ppm) in the dielectric barrier discharge (DBD), plasma-photocatalytic, hybrid system. The V (1.0, 5.0, 10.0 mol-%)-TiO 2 photocatalysts were prepared by using the conventional sol-gel method. Their surface areas were decreased with increasing vanadium component. The UV-visible absorption band slightly shifted to more visible wavelengths in V-TiO 2 compared to that in pure TiO 2 . The NH 3 -TPD result confirmed that the ability of NH 3 adsorption on the surface of V-TiO 2 increased with increasing vanadium content, and was maximized for 5.0-mol% V-TiO 2 . The NH 3 decomposition was enhanced with the photocatalyst compared to the decomposition rate without catalysts, while the decomposition was further increased with the applied plasma voltage. The NH 3 decomposition reached 90% after 400 min at an applied plasma voltage of 10.0 kV, and various intermediates, such as -NH 2 , -NH, and NO, were also identified by using the Fourier transform infrared (FT-IR) spectra. In addition, the NH 3 decomposition reached 100% in the plasma-5.0 mol% V-TiO 2 , photocatalytic, hybrid system after 25 min, compared to 98% in the pure V-TiO 2 photocatalytic system after 150 min. In addition, the various undesirable byproducts were depressed when V-TiO 2 photocatalyst was used compared to that in the non-catalytic system.