Research On Preparation Of Iron, Chrome Based Nanoparticles By Low Temperature Combustion Synthesis And Their Applications

Due to their special structure. nanomaterials present some unusual light, electricity, heat, magnetism or force properties. Especially iron and chromium based nanomaterials (oxide, nitride and carbide) have draw attention by more and more researchers. Up to now, they have applications in the area of energy, lithium ion batteries, catalysis, environment, and so forth. In this paper, low temperature combustion synthesis (LCS) and reduction method were combined to prepare iron and chromium based nanomaterials, and the process of preparation for oxide and non-oxide ceramic powders were investigated in detail. The main research work of the paper focused on several aspects as follows:(1) The mesoporous iron oxide based nanopartieles have been synthesized by LCS, the reaction mechanism of preparation of iron oxide based materials was investigated and glycine to ferric nitrate (G/F) influence on the synthesis of α-Fe2O3 nanoparticles. the content of doped Sn influence on the synthesis of Sn-α-Fe2O3 and the content of glucose influence on the synthesis of C@α-Fe2O3 have been studied. The N doped amorphous iron oxide/carbon composite has been successfully synthesized. The photodegradation of iron oxide based materials were evaluated. The results showed that the G/F, the content of Sn and the content of glucose have great influence on the special surface area, size and morphology of the nanoparticles. When the G/F is 0.3, the as prepared mesoporous α-Fe2O3 with a high special surface area of 103 m2/g and an average size of 20 nm and the product can absorb visible light. A α-Fe2O3 (0.05g) as the photocatalyst was added to an 100 ml MB solution of concentration 20 mg/L with completed degradation within 100 min. Element doped can improve the performance of the photoactivity and 0.05g 5% Sn-α-Fe2O3 can degrade the 100 ml MB solution of concentration 20 mg/L in 70 min.0.05g 12C@α-Fe2O3 can degrade the 100 ml MB solution of concentration 40 mg/L in 15 min.0.05g N doped amorphous iron oxide/carbon composite) can degrade the 100 ml MB solution of concentration 40 mg/L in 5 min.(2) Fe3C and its composites were prepared by carbothermal reduction the LCS precursor. The phase change process during the carbothermal reduction, the content of glucose influence on the characterizations of the Fe3C nanoparticles and the preparation of graphite encapsulated Fe3C composites were investigated in detail. The results showed that the precursor was not transformed to iron oxide, directly changed amorphous iron oxide to Fe3C during carbothermal reduction process. The content of glucose have great influence on the special surface area, size and morphology of the Fe3C nanoparticlres. When the glucose concentration is 5 g, the precursor has the highest reactivity and the well distributed and crystalline Fe3C can be prepared at the temperature of 550℃ for 2h. The graphite encapsulated Fe3C Fe3C/Fe and Fe composites have been successfully synthesized and the phase in the composites could be adjusted by tuning the reaction temperature. Meanwhile, the composites have application in non-noble metal eletrocatalysis for hydrogen evolution reaction.(3) The Cr2O3 nanoparticles have been synthesized by LCS, and the molar ratio of glycine to chromium nitrate (G/C) influence on the synthesis of Cr2O3 nanoparticles and the mesoporous Cr2O3 with high special surface area as anode materials for lithium ion batteries were investigated. The results showed that the gas and energy liberated from the combustion reaction are different depending on the G/C, which have great influence on the size, morphology and special surface area of the nanoparticles. When the G/C is 4. the as prepared mesoporous Cr2O3 with a high special surface area of 162 m2/g and an average size of 20 nm, As an anode electrode materials for rechargeable lithium ion batteries, the mesoporous Cr2O3 nanoparticles displayed enhanced electrochemical performance. Stable and reversible capacity of 480 mAh/g after 55 cycles is demonstrated.(4) The CrN nanoparticle has been synthesized by ammonolysis of the precursor prepared by LCS and the molar ratio of glycine to chromium nitrate (G/C) and the addition of the glucose influence on the synthesis of CrN nanoparticles were investigated. The results showed that the G/C has great influence on the nitridation reactivity, size and morphology of the CrN nanoparticlres. When the G/C is 4, the precursor has the highest nitridation reactivity and the as prepared CrN exhibited the homogeneous and small size of 30 nm. The size and morphology of the CrN can be controlled by the addition of glucose. It can be prepared well distributed and crystalline CrN nanoparticle at the temperature of 750℃ for 6h. The as prepared CrN nanoparticles can be used as catalyst support for noble metal.