α-Fe2O3 as a photocatalytic material: A review

• α-Fe2O3 is useful in photocatalytic water treatment & water splitting applications.
• α-Fe2O3 has advantage of low band gap, chemical stability, low cost & nontoxicity.
• The property is restricted by high e−–h+ recombination rate & low diffusion length.
• The article summarizes different attempts to enhance the photocatalytic activity.
• The surface area & e−–h+ recombination rate control the photocatalytic property.

Photocatalysis has been attracting much research interest because of its wide applications in renewable energy and environmental remediation. There are many materials that are found to show good photocatalytic activity in the presence of ultraviolet (UV) and visible light. However, the applications of these materials are limited to the UV portion of sunlight. α-Fe2O3 has an advantage over the other conventional materials like TiO2, ZnO, etc. in using solar energy for photocatalytic applications due to its lower band gap ∼2.2 eV value. As a result of which Fe2O3 is capable of absorbing a large portion of the visible solar spectrum (absorbance edge ∼600 nm). Also its good chemical stability in aqueous medium, low cost, abundance and nontoxic nature makes it a promising material for photocatalytic water treatment and water splitting applications. Except these advantages the usage of Fe2O3 has been restricted by many anomalies such as higher e–h recombination effect, low diffusion length and VB positioning (VB is positive with respect to H+/H2 potential). This article reviews the research that has been carried out to overcome these basic limitations and to enhance the photocatalytic activity of α-Fe2O3.

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