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Presents a study which investigated the photodegradation process of aniline, 4-ethylaniline, and 4-chloroaniline in aqueous suspension of irradiated anatase powder. Methodology; Results; Discussion; Conclusions.

Presents a study which reported additional results obtained with a method already proposed and used to measure absorbed and reflected photons during the occurrence of heterogeneous process carried out in the presence of a polycrystalline semiconductor solid suspended in aqueous solution. Methodology; Results; Discussion.

Photoinduced reduction of CO by HO to produce CH and CHOH has been investigated on wellcharacterized standard TiO catalysts and on a Cu loaded TiO catalyst. The efficiency of this photoreaction depends strongly on the kind of catalyst and the ratio of HO to CO. Anatase TiO, which has a large band gap and numerous surface OH groups, shows high efficiency for photocatalytic CH formation. Photogenerated Ti ions, H and CH radicals are observed as reactive intermediates, by ESR at 77 K. Cu-loading of the small, powdered TiO catalyst (Cu/TiO) brings about additional formation of CHOH. XPS studies suggest that Cu plays a significant role in CHOH formation. [ABSTRACT FROM AUTHOR]

Two examples of photoreactions are reported in the present paper: namely the photoreduction of N to NH in the gas-solid regime and the complete photooxidation of phenol and nitrophenols in the gas-liquid-solid regime (aqueous oxygenated dispersions). Undoped pure and iron ion doped polycrystalline titania specimens were used as photocatalysts. The presence of the dopant, in the case of N photoreduction, was essential for the occurrence of the photoprocess; it was, on the contrary, detrimental or indifferent in the case of phenol and nitrophenols photooxidation. The influence of several ions as Cl, SO , Fe, Fe, Ag and of a compound such as HO added to the dispersion was also investigated and the different behaviour of TiO (anatase) and TiO (rutile) was ascribed to kinetic factors. [ABSTRACT FROM AUTHOR]