Atomic layer deposited (ALD) TiO2 and TiO2-x-N-x thin film photocatalysts in salicylic acid decomposition

Degradation of salicylic acid (SA) with thin film photocatalyst, titanium dioxide (TiO2) and nitrogen-doped TiO2 (TiO2-x-N-x) combined with ultraviolet (UV) radiation was studied. TiO2 film with thickness of 15 and 65nm was tested. The TiO2-x-N-x film had thickness of 15nm on top of TiO2 (50 nm). Photocatalysts were prepared on glass substrate by atomic layer deposition (ALD) technique. The effect of initial pH (3-10) was studied with SA concentration of 10 mg/l. Decomposition of SA was fastest at pH 6 with both films and the rate was equal at initial pH values 3 and 4.3. However, at higher pH values the non-doped film was more efficient.