Preparation, Gas Sensing And Photocatalytic Properties Of Iron Oxide With Special Morphology And Its Composites

As a kind of important functional materials, iron oxide has been studied extensively and used in many fields such as catalysts, magnetic materials, gas sensing materials, targeting drugs and electrode materials, due to its abundant sources, pollution-free, low cost, good chemical stability and excellent performance. The morphology and structure of iron oxide has a very strong influence on its properties, investigating the formation mechanism of different structure and morphology of iron oxide and their impact on the performance can facilitate the performance improvement and expanding the area of application of iron oxide materials by the means of materials designing.This paper used complexing agents such as C2O42-, EDTA, CN- to prepared a-Fe2O3 nano materials with special morphology under hydrothermal conditions, and studied their gas-sensing property and photocatalytic activity. The main content as follows:1, Lawn-like a-Fe2O3 film uniformly and firmly attaching on ITO conductive glass substrate has been produced under 180℃ hydrothermal conditions using Na2C2O4 and Fe(NO3)3 reactants. Iron oxide growing on ITO substrate and the product precipitating from aqueous solution have similar lamellar structure, they are stacked by nanometer wafers which is piled up by sheets, but the former is more orderly, the sheets pile up more closely, and the wafers grow nearly perpendicular to the ITO substrate. The formation mechanism of iron oxide film growing on ITO substrate was discussed. The investigation on gas-sensing property of the as-prepared iron oxide reveals fast response and high sensitivity to CH3CH2OH, CH3COCH3,2, Pompon-like a-Fe2O3 and FeC2O4-2H2O quadrangular columnar crystals with large size were prepared via a simply hydrothermal process by using EDTA, Fe(NO3)3 as reactants. The impact of temperature, ITO or PEG200 added or not on the morphology of the product was studied, and the formation mechanism of the product under different conditions was preliminarily discussed. To demonstrate the potential applications, the gas-sensing property of pompon-like a-Fe2O3 was investigated and compared with special flake-like a-Fe2O3. Results show that the special flake-like a-Fe2O3 sensor exhibits significantly improved sensor performances in comparison with the pompon-like α-Fe2O3. The enhancement of sensing properties is attributed to the unique loose nanostructure and larger specific surface area.3, Nanotree-like a-Fe2O3 was produced under hydrothermal condition using K4[Fe(CN)6] as raw material, afterwards, it was decorated with CdS by water-bath method. The photocatalytic activities of the as-prepared composite materials were investigated. Results show that the photocatalytic activity of the composites is superior to the pure a-Fe2O3 nanomaterials. The enhanced performance is associated with the larger surface area of the composites, the crystalline nature of the materials and the synergy in light absorption and charge separation between a-Fe2O3 and CdS.