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Two series of Ta 2 O 5 –TiO 2 photocatalysts (Ta:Ti = 4:1, 1:1 and 1:4) were prepared by sol–gel technique applying triblock copolymer of Pluronic P123 and were tested in platinized form (0.3 wt.%) in photodecomposition of water under ultraviolet and visible light ( λ > 300 nm). It was found the mesoporous character of tantalum containing catalysts with relatively high surface area (∼100–130 m 2 g −1 ) of these samples. However, higher concentration of TiO 2 in mixed oxides leads to the destruction of mesoporous character of synthesized photocatalysts. All samples were characterized with thermogravimetry, XRD, N 2 physisorption, DR-UV–vis and FTIR spectroscopy. The mixed oxides of Ta 2 O 5 –TiO 2 system showed much lower band-gap than pure Ta 2 O 5 and relatively high activity in platinized state in photocatalytic hydrogen generation under visible. Doping of pure oxides and mixed systems with sulfur resulted in lowering of the band-gap values below 3 eV and much better activity in H 2 evolution reaction. Non-platinized photocatalysts showed activity in liquid phase cyclohexene photooxidation at 305 K. |
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