TiO < inf > 2 < /inf > /SnO < inf > 2 < /inf > and SnO < inf > 2 < /inf > /TiO < inf > 2 < /inf > heterostructures as photocatalysts for degradation of stearic acid and methylene blue under UV irradiation

Abstract

The effect TiO 2 /SnO 2 (TiO 2 is on the top and SnO 2 at the bottom) and SnO 2 /TiO 2 (SnO 2 is on the top and TiO 2 at the bottom) heterostructures towards photocatalytic degradation of stearic acid and methylene blue is reported. The two heterostructures, wherein SnO 2 (or TiO 2 ) is the top or bottom layer, are prepared by the sol-gel technique. TiO 2 /SnO 2 film exhibit better photocatalytic activity as compared to SnO 2 /TiO 2 , TiO 2 and SnO 2 films. Wettability studies reveal that TiO 2 /SnO 2 films modified with stearic acid (8 mM concentration of stearic acid in ethyl alcohol) tend towards superhydrophobic regime with contact angle as high as 137°. Further, TiO 2 /SnO 2 films are efficient in degrading the stearic acid under UV irradiation. Interestingly, TiO 2 /SnO 2 films that display flake like structures, with increased charge separation, are responsible for better degradation of pollutants under UV irradiation because of coupling heterostructures.