Microwave-assisted hydrothermal synthesis of a-Fe2O3 on flavin mononucleotide-stabilized graphene nanosheets as potential counter electrode for sensitized photovoltaic cells

• Main Author: CABELLO, MARK KRISTAN
• Format: text
• Published: Archīum Ateneo 2017
• Subjects: Graphene; Graphene > Oxidation; Microwave heating; Nanocomposites (Materials); Nanostructured materials; Photovoltaic cells > Research.
• Online Access: https://archium.ateneo.edu/theses-dissertations/82; http://rizalls.lib.admu.edu.ph/#section=resource&resourceid=1316179587&currentIndex=0&view=fullDetailsDetailsTab
• Institution: Ateneo De Manila University

This study offers facile and environment-friendly nanocomposite synthesis of a-Fe2O3 dispersed on Flavin Mononucleotide-stabilized graphene in aqueous medium. The new method for nanocomposite synthesis was done via microwave-assisted hydrothermal synthesis. The study was done in two-parts: synthesis of a-Fe2O3 on aqueous medium and fabrication of a-Fe2O3/graphene using optimized method. a-Fe2O3 was synthesized in a basic solution of FeCl3.6H2O and hexamethylenetetraamine at 130 oC for 65 minutes with microwave radiation. The characterization for the nanocomposite was done using SEM-EDX, XRD, DLS, FTIR, UV-Vis, UV-DRS, TGA, AFM and CV (for Fe(CN)6 4-/3-). Based on the results, a-Fe2O3 was successfully synthesized using the developed method. The optimum microwave parameter to be used are 5 min ramp time at 300 W, 60 mins hold time at 80 W and cooled to 55 oC. It was observed that the particle size from microwave synthesis was -52 nm, which is smaller compared to traditional hydrothermal synthesis (100 200 nm). Interestingly, the hydrodynamic diameter size of the nanoparticles decreases as the hold time of the microwave synthesis is decreased. Moreover, the newly devised method was applicable for the synthesis of a-Fe2O3/graphene nanocomposite. It was observed that Flavin mononucleotide is an effective stabilizing agent for the dispersion of a-Fe2O3 on the graphene nanoparticles. The highest catalytic activity towards Fe(CN)6 4-/3- redox reaction was seen using -58.3% a-Fe2O3 loading a-Fe2O3/graphene nanocomposite at 70 mA/mm2 current density.