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Nitrogen-doped titania photocatalysts were prepared from titanium tetraisopropoxide or titanium tetrachloride and thiourea. The yellow powders obtained after calcination at 400−600 °C photocatalyze the mineralization of 4-chlorophenol by visible light (λ ≥ 455 nm). Different from previously published data these materials do not contain sulfur but instead nitrogen as the doping component inducing visible light photocatalysis. The measured band gap narrowing of 40−80 meV and the anodic shift of the quasi Fermi potential of 40−90 mV are in agreement with recent results on nitrogen-doped titania.

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Bi 3 YO 6 , which is known as an ionic conductor, was tested here as an electrode and photoanode in contact with aqueous electrolytes. Bi 3 YO 6 was deposited onto the Pt substrate and the such prepared electrode was polarized in various aqueous electrolytes. The optical energy band gap of the material equal to 1.89 eV was determined using the Kubelka-Munk function resulting from the UV-Vis spectrum (allowed indirect transition) and also was calculated using the semi-empirical PM7 method (3.38 eV of HOMO-LUMO energy gap). Despite the yellow color of Bi 3 YO 6 , the tested material exhibits photoelectroactivity only in the UV range of electromagnetic radiation. The anodic photocurrent characteristic for n-type metal oxide semiconductors was recorded. The electrode exhibits diffusion-controlled cathodic activity while polarized in chloride-free aqueous electrolytes.