Synthesis and characterization of an α-Fe2O3/ZnTe heterostructure for photocatalytic degradation of Congo red,methyl orange and methylene blue |
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| Authors: | Rooha Khurram Zhan Wang Muhammad Fahad Ehsan Song Peng Maryam Shafiq Bushra Khan |
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| Institution: | Beijing Key Laboratory for Green Catalysis and Separation, Department of Chemistry and Chemical Engineering, Beijing University of Technology, Beijing China, Fax: +86-10-6739-1983, +86-10-6739-6186 ; Department of Chemistry, School of Natural Sciences (SNS), NUST, H-12, Islamabad Pakistan.; Department of Chemistry, Cape Breton University, 1250 Grand Lake Road, Sydney NS B1P 6L2 Canada |
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| Abstract: | The leading challenge towards environmental protection is untreated textile dyes. Tailoring photocatalytic materials is one of the sustainable remediation strategies for dye treatment. Hematite (α-Fe2O3), due to its favorable visible light active band gap (i.e. 2.1 eV), has turned out to be a robust material of interest. However, impoverished photocatalytic efficiency of α-Fe2O3 is ascribable to the short life span of the charge carriers. Consequently, the former synthesized heterostructures possess low degradation efficiency. The aim of the proposed endeavor is the synthesis of a novel zinc telluride-modified hematite (α-Fe2O3/ZnTe) heterostructure, its characterization and demonstration of its enhanced photocatalytic response. The promising heterostructure as well as bare photocatalysts were synthesized via a hydrothermal approach. All photocatalysts were characterized by the X-ray diffraction technique (XRD), scanning electron microscopy (SEM), and electron diffraction spectroscopy (EDX). Moreover, the selectivity and activity of the photocatalyst are closely related to the alignment of its band energy levels, which were estimated by UV-Vis diffuse reflectance spectroscopy (DRS) and X-ray photoelectron spectroscopy (XPS). Nanomaterials, specifically α-Fe2O3 and α-Fe2O3/ZnTe, were used for the degradation of Congo red (97.9%), methyl orange (84%) and methylene blue (73%) under light irradiation (>200 nm) for 60 min. The results suggested that with the aforementioned optimized fabricated heterostructure, the degradation efficiency was improved in comparison to bare hematite (α-Fe2O3). The key rationale towards such improved photocatalytic response is the establishment of a type-II configuration in the α-Fe2O3/ZnTe heterostructure.Effective generation and transportation of electron–hole pairs in the presence of light leads to efficient degradation of textile pollutants over an α-Fe2O3/ZnTe nanocomposite compared to the individual components. |
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