New graphene-Co_xZn_{1∿span style='font-style: italic'>x}Fe₂O₄ nano-heterostructures: Magnetically separable visible light photocatalytic materials

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• 作者：Sidra Nazim^a ; Tehmina Kousar^a ; Muhammad Shahid^a ; Muhammad Azhar Khan^b ; Gulfam Nasar^a ; Muhammad Sher^c ; Muhammad Farooq Warsi^a ; ^{farooqwarsi@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; ^{farooq.warsi@iub.edu.pk" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Graphene ; Nano-heterostructures ; Photocatalysis ; Magnetically separable ; Visible light
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：1 May 2016
• 年：2016
• 卷：42
• 期：6
• 页码：7647-7654
• 全文大小：1673 K

文摘

Magnetic Co_xZn_1−xFe₂O₄ nanoparticles and Co_xZn_1−xFe₂O₄-graphene nano-heterostructures were prepared by chemical co-precipitation route and ultra-sonication method respectively. The characterization of Co_xZn_1−xFe₂O₄ nanoparticles was carried out by thermo-gravimetric analysis (TGA), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy, vibrating sample magnetometry (VSM). TGA predicted the phase formation temperature around 850 °C. XRD and FTIR confirmed the single phase cubic structure. Crystallite size as calculated by Scherrer׳s formula was found 50–70 nm; however the nanoparticles size determined by TEM was found 35–75 nm. VSM confirmed the ferromagnetic nature of both ZnFe₂O₄ and Co_0.3Zn_0.7Fe₂O₄ nanoparticles. The reduced graphene oxide (rGO) prepared by modified Hummer׳s method was characterized by UV–visible (UV–vis) spectroscopy and XRD. As prepared rGO was utilized for preparation of Co_xZn_1−xFe₂O₄-rGO nano-heterostructures. SEM confirmed the well dispersed Co_xZn_1−xFe₂O₄ nanoparticles among rGO sheets. Electrochemical impedance spectroscopy (EIS) studies of Co_xZn_1−xFe₂O₄ nanoparticles and their nano-heterostructures with rGO showed that Co_xZn_1−xFe₂O₄ nanoparticles exhibit the high charge transfer resistance as compared to nano-heterostructures. The photocatalytic efficiency of Co_xZn_1−xFe₂O₄ nanoparticles and their nanocomposites with rGO was evaluated using methylene blue as model organic compound in the presence of visible light. The Co_xZn_1−xFe₂O₄-rGO nano-heterostructures showed more efficiency as compared to Co_xZn_1−xFe₂O₄ nanoparticles. The ferrite nanoparticles and their nano-heterostructures with rGO could be separated and recycled by conventional magnetic bars easily.