PHOTOCATALYTIC ACTIVITY OF ARTIFICIAL TITANIUM(IV) OXIDE-<TEX>$TIO_2(B)$</TEX>-AND TITANATES SUSPENDED IN AQUEOUS SOLUTION OF ALIPHATIC ALCOHOLS

Powders of artificial crystallites of titanium(IV) oxide, TiO$_2$(B), were synthesized by the calcination of tetratitanic acid (hydrate, $H_2Ti_4O_9H_2O$; TTA). The relating titanates, potassium octatitanate ($K_2Ti_8O_{17}$) and octatitanic acid($H_2Ti_8O_{17}$), were also prepared. These powders, loaded with small amount of Pt, were suspended in an aqueous solution of 2-propanol and irradiated under argon atmosphere at 298 K + 0.5 deg. All the photocatalysts tested in this study produced almost equimolar amount of acetone and molecular hydrogen (H$_2$). Among them TiO$_2$(B) and TYA showed the higher photocatalytic activity but rather lower than commercial titanium(IV) oxide (TiO$_2$) powders. The photocatalytic activity of TiO$_2$(B) for 2-propanol dehydrogenation in deaerated aqueous suspension increased with the elevating calcination temperature. Comparison of rate of H$_2$ formation from methanol and 2-propanol solutions by the TiO$_2$(B) photocatalyst suggested a possibility of selection of substrate with its molecular size by TiO$_2$(B)