Photocatalytically active

A debate centers on the mechanistic details of heterogeneous photocatalysis. The goal is to improve the photocatalytic activity of Ti02, and understand the role and importance of mineralisation by (/) free versus surface bound oxidising radicals, OH, and (2) by surface OH radicals versus direct hole oxidation. 

The photochemistry of transition metal 1,3-diketone chelate complexes has been known for some time [30,31], and their photophysical and photochemical properties and photocatalytic activity in different chemical reactions were reviewed in 1990 by Marciniak and Buono—Core [32]. Further discussion on the photochemistry of meta] chelate will not take place here since this subject is out of the scope of this chapter. 

Table 1 Surface area, band gap energies and photocatalytic activities for H2 evolution from an electrolsde solution over single CdS and CdS-based composite photocatalysts.

Hydrothermal synthesis of titanium dioxides using acidic and basic peptizing agents and their photocatalytic activity on the decomposition of orange II... 

Where C is initial concentration of the orange II and A is a rate constant related to the reaction properties of the solute which depends on the reaction conditions, such as reaction temperature, pH of solution. The photocatalytic activity increases with an increase in this value. 

Table 1. Physical properties of nanosized TiOj powders prepared at different HNO3 and TENOH concentration and their photocatalytic activity...

The photocatalytic activity of 20mesh wire-net photocatalyst was observed to be nearly equal to that of 350mesh one under the same amount of titanium dioxide loading (1.88 g). 

In the presence of H2O2, Ti02/Cr-Ti-MCM-41 showed a marked increase in photocatalytic activity for decomposition of 4-NP over Ti02/Cr-Ti-MCM-41 in visible light. H2O2 increases the reaction rate by the promotion of adsorption of reactant and the removing of surface-trapped electrons. 

The photocatalytic reactivity for TCE decomposition was increased by platinization and the photocatalytic activity of the catalysts prepared with leached solution fi-om wasted automobile catalyst was similar to that of the catalysts modified with H2PtCl6. 

Effect of surface modification by low temperature plasma on the photocatalytic activity of TiOi thin film... 

In this work, Ti02 films prepared by sol-gel method were surface-modified by treating the surface with low temperature plasmas. And, effects of the modifications on the photocatalytic activity of the films under UV-A and fluorescence light were investigated. 

After the modifications, light absorbance of a Ti02 film at wavelengths longer than 350 nm was increased up to almost 4.0 times (see Fig. 1). As a consequence, photocatalytic activity under both UV-A and fluorescent light was hi y improved. Extent of the improvement was dependent on treatment conditions. The optimum treatment conditions are listed in Table 1. 

To enhance the formation of Ti species by reduction and nitration together, treatment with H2+N2 plasma and H2+Ar/N2+Ar (H2+Ar treatment followed by N2+Ar) were tried. However, there was no further improvement. H2+Ar/N2+Ar plasma treatment reduced the optimum treatment time to 20 minutes but improvement of photocatalytic activity imder fluorescent light was just 2.0 times. H2+Ar pretreatment seems to make substitutional doping of N easier through reduction reaction. 

O2 plasma treatment was also effective for the improvement of photocatalytic activity. Although the improvement was not as high as H2+Ar or N2+Ar plasma treatments, O2 plasma treated films show photocatalytic activities up to 1.3 times higher under UV-A and up to 1.7 times higher under fluorescent light than an untreated film. According to ESCA analysis, the improvements seem to attribute to the cleaning effect of O2 plasma. 

In this work, effect of atmosphere during calcination process on surface defect was investigated using photocatalytic activity for oxidation of ethylene. CO2-TPD and ESR were used to determine this surface defect. 

In this work, we aimed to investigate the effect of doping nitrogen on the characteristics and demonstrate the feasibility of improvement of photocatalytic activity of Ti02 under visible light. 

On account of the reported photocatalytic activity of titania nanosheets in the oxidation of water [290], Yamada et al. [291] attempted to fabricate photoelectrodes responsive to visible light by coating Cd8 electrodes with titania nanosheets. It was considered that since the thickness of a nanosheet is as small as two atomic layers of... 

Pal B, Torimoto T, Iwasaki K, Shibayama T, Takahashi H, Ohtani B (2004) Size and structure-dependent photocatalytic activity of jingle-beU-shaped silica-coated cadmium sulfide nanoparticles for methanol dehydrogenation. J Phys Chem B 108 18670-18674... 

Effect of Tunnel Structures of BaTi409 and Na2TieOi3 on Photocatalytic Activity and Photoexcited Charge Separation... 

Since BaTi40g and Na2TieOi3 have a pentagonal prism tunnel and a rectangular tunnel structure, respectively, we have paid attention to the role of the tunnel structures in photocatalysis. A barium titanate, Ba4Tii303o, in a series of Ba-Ti titanates was chosen as a representative with non-tunnel structure, and we have compared the photocatalytic activity and the ability for the production of surface radical species with uv irradiation between the tunnel and the non-tunnel titanates. 

The photocatalytic activity of [Ir(SnCl3)5FI]3 in the dehydrogenation of methanol to give dimethoxymethane and dihydrogen is described.80,81 Tra .s-[IrClF[(SnCl3 )4]3 and trans-... 

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