Photocatalytic reaction on photofuel cell titania electrode

Benzoic acid-doped titania electrodes were prepared from titanium alkoxide sols containing benzoic acid in order to examine the photocatalytic reaction of the fuel material concentrated on the titania surface of a photofuel cell electrode. This doping was developed in order to understand the physicochemical processes on the titania rather than to advance the practical use of the photofuel cells. The observed photocurrent and CO(2) and H(2)O productions indicated that the oxidation of the benzoic acid enhanced the generation of electricity during the UV irradiation. Benzoic acid molecules should be oxidized by oxygen molecules and holes on the titania surface. The steam treatment of the electrodes improved the benzoic acid oxidation and the photocurrent because it promoted the titania densification and enhanced the interaction between the benzoic acid and titania. The benzoic acid-doped titania is a valid model of the fuel material concentrated in the porous titania when using benzoic acid as the fuel material. The contact between the benzoic acid and titania is important in order to obtain a high photofuel electric conversion.ArticleRESEARCH ON CHEMICAL INTERMEDIATES. 38(1):241-250 (2012)journal articl

Degradation of trichloroethylene using highly adsorptive allophane-TiO(2) nanocomposite

A highly adsorptive allophane-TiO(2) nanocomposite photocatalyst was prepared by dispersing nanopartides of the natural clay mineral allophane into a titanium alkoxide solution by the sol-gel method. During the photocatalytic degradation of trichloroethylene using the allophane-TiO(2) nanocomposite, emission of the intermediate product, phosgene, was drastically inhibited. Trichloroethylene was transformed into the intermediate products, phosgene and dichloroacetyl chloride, on the TiO(2) during the UV irradiation. These compounds are rapidly adsorbed on the allophane. The compounds then gradually degraded after diffusing to the TiO(2).ArticleAPPLIED CATALYSIS B-ENVIRONMENTAL. 102(3-4):470-474 (2011)journal articl

Photoinduced reactions of chloroacetone in solid Ar: Identification of CH2=COCICH3

The UV light-induced reactions of chloroacetone in a cryogenic Ar matrix were investigated using infrared spectroscopy. The photoinduced isomerisations of gauche-chloroacetone to syn-chloroacetone and hypochlorous acid 1-methylethenyl ester were confirmed by comparing the experimental and calculated spectra. In addition, the photolysis products were found to be CH2double bond; length as m-dashCdouble bond; length as m-dashO and a cyclopropanone⋯HCl complex. The cyclopropanone⋯HCl complex was further decomposed into CH2double bond; length as m-dashCH2, CO and HCl. The hypochlorous acid 1-methylethenyl ester was further isomerized to 2-chloro-2-methyloxirane.ArticleCHEMICAL PHYSICS LETTERS. 614:258-262 (2014)journal articl

Photoinduced electron transfer in rhodamine B-containing amorphous titania gels

Amorphous titania gel films containing the dye rhodamine B (RhB) were prepared by a sol-gel method, without heating. The RhB existed in the films as the RhB cation, which was transformed into the rhodamine 110 (Rh110) cation; its xanthene skeleton then decomposed during irradiation with visible light. This process was induced by electron transfer from the RhB cation to the titania gel matrix, because formation of the RhB radical on loss of an electron caused sequential dissociation of the N-ethyl groups. During irradiation with visible light a photocurrent was observed in electrodes coated with the RhB-containing titania gel and immersed in an I-2-LiI electrolyte. This photocurrent resulted from electron injection from the LUMO level of the dye into conduction band-like states of the titania gel. Because of its effective electron supply the electrolyte inhibited dissociation of the N-ethyl groups of RhB.ArticleRESEARCH ON CHEMICAL INTERMEDIATES. 41(6):3803-3816 (2015)journal articl

Reaction of spironaphthoxazine with acid

The reaction of spironaphthoxazine (SNO) with acid in ethanol was investigated by spectroscopic analyses SNO was protonated and then transformed into a complex in an acidic ethanol solution in the dark. It is presumed that the complex contains a hydrated proton and its structure is similar to that of the metal complex of a merocyanine-type isomer photoderived from SNO based on its UV-vis absorption and fluorescence spectra. The complex dissociated into SNO by adding base. The complex was further changed under acidic conditions after a long time. Highly concentrated acid decomposed SNO to an indoline compound having a carboxyl group and 1-amino-2-naphthol, which was revealed by fluorescence, IR, and GC-MS analyses. These reaction processes were promoted by UV irradiation.ArticleJOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY. 252:100-106 (2013)journal articl

Chelation ability of spironaphthoxazine with metal ions in silica gel

Spironaphthoxazine (SNO) and three metal ions, Mg2+, Zn2+, and Al3+, were dispersed in silica gels by the sol-gel method. The chelation ability of SNO with the metal ions in silica gels was investigated by measuring the fluorescence spectra and was compared to that of 8-hydroxyquinoline (8-HQ) in ethanol and silica gels. A merocyanine-type isomer photoderived from SNO as well as 8-HQ easily formed complexes of the metal ions in the order of Al3+, Zn2+, and Mg2+ because the coordination ability of the metal ions to such ligands depended on their electron affinity. The changes in the fluorescence spectra of the silica gel samples during light irradiation were also investigated. The relative band intensity due to the intermediate species between the original SNO and the merocyanine species decreased and that of the complex increased with the UV irradiation time. The reverse process was observed during visible irradiation. The UV irradiation effects on the chelation of SNO and its photochromic property also depended on the electron affinity of the metal ions.ArticlePHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES. 11(7):1164-1173 (2012)journal articl

Density functional theory studies on the addition and abstraction reactions of OH radicals with terephthalate dianions

The addition and abstraction reactions of OH radicals with terephthalate dianions are investigated by density functional theory calculations that include solvent effects. Geometry optimizations of the reactants, products, and transition state species are performed for the potential reaction paths. For the addition reactions, those targeting the ipso- and ortho-carbons are predicted to be exoergic. The H-atom abstraction reaction is also predicted to be exoergic. On the basis of the rate constants calculated by means of the transition state theory, the H-atom abstraction reaction is determined to be the thermochemically favored path. (C) 2012 Wiley Periodicals, Inc.ArticleINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY. 113(4):418-422 (2013)journal articl

Computational study of the reaction between chloroacetone and OH radical

In this study, the reaction of the chloroacetone with OH radical was studied theoretically using density functional theory (DFT) and transition state theory. The potential energy surface of the reaction was calculated at the CAM-B3LYP/6-311++G(2d,2p) and M06-2X/6-311++G(2d,2p) levels. We initially considered four possible reaction paths: (1) the hydrogen atom abstraction from chloroacetone by OH radical; (2) the addition of the OH radical to the carbonyl carbon; (3) chlorine atom abstraction; and (4) SN2 displacement. The conventional transition state theory was employed to calculate the rate constants. The hydrogen abstraction from the ?CH2Cl group was found to be dominant. Since, the predicted total rate constant at the CAM-B3LYP/6-311++G(2d,2p) level was in good agreement with the experimental value at 298 K, the level of theory used in this study to describe this reaction is appropriate.ArticleCOMPUTATIONAL AND THEORETICAL CHEMISTRY. 1020:108-112 (2013)journal articl

Photofuel cells using glucose-doped titania

Glucose-doped titania electrodes were prepared from titanium alkoxide sols containing glucose in order to examine the validity of the fuel material concentrated on the photocatalyst surface. The observed photocurrent and CO(2) and H(2)O productions indicated that the oxidation of the glucose enhanced the generation of electricity during the UV irradiation. Steam treatment of the electrodes improved the glucose oxidation and the photocurrent. However, refluxing of the precursor sol did not improve them. Not only the titania conductivity, but also the contact between the glucose and titania is important in order to obtain a high photofuel electric conversion. The concentration of the fuel material on the photocatalyst surface improved the energy conversion efficiency.ArticleAPPLIED CATALYSIS B-ENVIRONMENTAL. 106(1-2):250-254 (2011)journal articl

Matrix isolation studies of 185 nm light-induced cage reactions of o-chlorobenzaldehyde

VUV light photolysis of o-chlorobenzaldehyde (CBA) has been investigated by infrared spectroscopy in cryogenic Ar and O-2 matrices. Previously reported photoinduced rotational isomerization from anti- to syn-CBA was confirmed in the Ar matrix. In addition, absorption bands associated with photoinduced rearrangement to benzoyl chloride were observed accompanying the weak bands due to the CO photolysis product. However, in the reactive O-2 matrix, isomerization was observed and there was no evidence of benzoyl chloride formation. A kinetic analysis revealed that rearrangement was a minor process under the present excitation energy. The TD-B3LYP calculations show that as the excitation energy increases the predissociation channel will open and the repulsive (1)(pi, sigma(c-a)*) and 1(eta, sigma(c-a)*) states are directly achievable by the 185 nm excitation. Photoinduced rearrangement will be caused by the reaction of thus dissociated cage pairs.ArticleJOURNAL OF MOLECULAR STRUCTURE. 1025:48-52 (2012)journal articl