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Hydrothermal Synthesis of Hierarchical Hematite (α-Fe2O3) Microstructures for
Photocatalytic Degradation of Methyl Orange

Nick Joaquin Rapadas and Mary Donnabelle L. Balela

Sustainable Electronic Materials Group
Department of Mining, Metallurgical, and Materials Engineering
University of the Philippines Diliman, Quezon City 1101, Metro Manila, Philippines

*Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

 

ABSTRACT
Hematite (α-Fe2O3) hierarchical microstructures were prepared by a simple and inexpensive hydrothermal method using a mixture of FeCl3 and Na2SO4 as precursors, followed by annealing at 400o C for 2 h. α-Fe2O3 microspheres with an average diameter of 1.07 µm were formed in the solution.  Microrods with an average length of 0.46 µm were also observed on the surface of the microspheres, forming an urchin-like morphology. The amounts of Fe3+ and (SO4)2- in the solution significantly influence the morphology of the α-Fe2O3 urchin-like microstructures. An optimum amount of Fe3+ and (SO4)2- leads to the formation of urchin-like microstructures. The α-Fe2O3 microstructures successfully degraded methyl orange after 1 h of UV irradiation in the presence of a minute amount of hydrogen peroxide (H2O2). The α-Fe2O3 microstructures also exhibit excellent reusability and stability making it an ideal photocatalyst for wastewater treatment.

 

INTRODUCTION
The use of iron oxide nanomaterials, particularly hematite, is prevalent in various fields due to potential applications, such as gas sensing (Abe et al. 1997, Zhang et al. 2009), wastewater treatment (Hua et al. 2012), photocatalysis (Verhoeven 1996, Mishra & Chun 2015), photovoltaics (Gotić et al. 2011), field-emission (FE) devices (Hsu et al. 2011), and glucose sensing (De Mesa et al. 2011).  Thus, different synthesis methods for iron oxide nanomaterials have been studied extensively. In particular, hematite (α-Fe2O3) nano and microstructures are promising photocatalysts. Substantial efforts have already been made to prepare α-Fe2O3 with various morphologies (Atabaev, 2015). Examples include nanowires (Chirita & Grozescu 2009), nanorings (Mohapatra & Anand 2010), hollow spheres (Yu et al. 2009), nanorods and capsules (Sun et al. 2012). The physical and chemical properties of α-Fe2O3 nano and microstructures are influenced by the morphology. Thus, much research has been focused on controlling the morphology, as well as in the fabrication of complex structures. For example, in hydrothermal synthesis, the morphology of . . . . read more

 

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