Fabrication of SnO₂/α-Fe₂O₃, SnO₂/α-Fe₂O₃-PB heterostructure thin films: enhanced photodegradation and peroxide sensing.

We report the synthesis of SnO2/α-Fe2O3 heterostructure thin films by employing two-step processes: galvanic and chemical deposition. Fe2O3 is a narrow band gap semiconductor and has short hole diffusion length. Therefore, the photogenerated electrons and holes are not easy to separate in Fe2O3. Combining Fe2O3 to SnO2, a wide-energy-gap semiconductor having suitable valence band and conduction band position is a promising candidate for the photo catalysts. The chemical modification of this heterostructure was achieved by electro-active Prussian blue (PB) molecule. The photocatalytic activities of SnO2, α-Fe2O3, SnO2/α-Fe2O3, and SnO2/α-Fe2O3-PB thin films were investigated for organic dye degradation. It was observed that the coupled and combined modified systems showed better reactivity compared to individual single-component materials. The electrocatalytic activity of the synthesized thin films has also been studied where hydrogen peroxide (H2O2) was taken as a model compound. Amperometric study also reveals that the couple and combined modified thin films are more effective at sensing hydrogen peroxide (H2O2) than single-component materials.