The Photoelectric Properties Of Ultrafine?-Fe₂O₃ Nanoparticles And Graphene Compound

Hematite?a-Fe₂O₃?is considered as one of the most promising photocatalytic materials because of its stable chemical properties,wide source,environmental friendliness and suitable band gap width?1.9-2.2 eV?.However,the low conductivity,poor absorption coefficient and easy agglomeration of nanoparticles of ferric oxide monomer have seriously affected its wide application in the field of photocatalysis.The specific surface area is an important factor to measure the photocatalytic efficiency.Large specific surface area can provide more adsorption sites and reactive sites for photocatalytic materials,thus improving the photocatalytic degradation rate.In addition,carbon-based materials represented by graphene have excellent electronic transport properties and large specific surface area.Using graphene as carrier to construct nanocomposite photocatalytic materials can produce synergistic effect and significantly improve the photocatalytic activity of the materials.Therefore,the construction of ultra-small nanoparticles with large specific surface area and their graphene complexes has become one of the potential hot spots in the field of iron oxide-based photocatalytic materials.Ultrafine?-Fe₂O₃ nanoparticles and self-assembly?-Fe₂O₃ ultrathin round plate were prepared by hydrothermal method.By doping different ratios of reduced graphene oxide?rGO?,ultrafine?-Fe₂O₃ nanoparticles/rGO composites and self-assembly?-Fe₂O₃ ultrathin round plate/rGO composites were constructed.Their photocatalytic properties were systematically studied.?1?Using ferric chloride and sodium dihydrogen phosphate as raw materials,ultrafine?-Fe₂O₃ nanoparticles with particle size of 5.5?0.9 nm were synthesized by hydrothermal method.The photocurrent response of the composites doped with 5wt%rGO was measured by doping different ratios of rGO.The photocurrent of the composites doped with 5wt%rGO was 0.46mA/cm²,which was 1.8 times of pure ultrafine?-Fe₂O₃ nanometer?0.25mA/cm²?.Under ultraviolet irradiation,different dyes were degraded on the undoped rGO ultrafine particles and the doped 5wt%rGO composite respectively.It took 40-50 minutes for the two samples to degrade the cationic rhodamine B completely,and the catalytic efficiency of the composite doped5wt%rGO was 25%higher than that of the pure ultrafine?-Fe₂O₃ nanoparticles.?2?Using ultrafine?-Fe₂O₃ nanoparticles as seeds and changing the reaction concentration and reaction conditions of ferric chloride and sodium dihydrogen phosphate,the?-Fe₂O₃ ultrathin round plate with a thickness of 6nm and a diameter of 90±10 nm was self-assembled.The photocurrent response was measured by doping different ratios of rGO.The photocurrent of the composite material doped with 15wt%rGO was 0.61 mA/cm²,which was 7.6times higher than that of the?-Fe₂O₃ ultrathin round plate?0.08 mA/cm²?.Under visible light irradiation for 4 hours,different dyes were degraded on undoped rGO ultrathin round plate and 15wt%rGO-doped composite respectively.The two samples showed better degradation rates of cationic RhB,89.4%and 93.8%.