Visible‐Light Photocatalytic Degradation of Methylene Blue Using SnO₂/α‐Fe₂O₃ Hierarchical Nanoheterostructures

Three‐dimensional SnO 2 /α‐Fe 2 O 3 semiconductor hierarchical nanoheterostructures were synthesized for photocatalysis through a low‐cost and environmentally friendly hydrothermal strategy, by crystallographic‐oriented epitaxial growth of SnO 2 on three‐dimensional α‐Fe 2 O 3 flowerlike hierarchical nanostructures. In this photocatalyst, visible‐light‐active Fe 2 O 3 flowerlike hierarchical nanostructures were used as a medium to absorb photons and convert them into photogenerated charges, and SnO 2 nanoparticles were used as charge collectors to transport the photogenerated charges. The SnO 2 /α‐Fe 2 O 3 semiconductor hierarchical nanoheterostructures exhibited excellent visible‐light photocatalytic ability for the degradation of methylene blue; this was attributed to the large specific surface area, wide visible‐light absorption range, and efficient electron–hole pair separation properties of the SnO 2 /α‐Fe 2 O 3 nanoheterostructures. The SnO 2 /α‐Fe 2 O 3 material showed improved separation of photogenerated electron–hole pairs owing to the potential‐energy differences between SnO 2 and α‐Fe 2 O 3 , and therefore exhibited enhanced photocatalytic activity. This paper highlights the SnO 2 /α‐Fe 2 O 3 semiconductor hierarchical nanoheterostructures as potentially more environmentally friendly materials for use in organic pollutant degradation for environmental pollution cleanup operations.