| In recent year,Considerable interests have been focused on oxides due to their novel physical and chemical properties and their potensial application in some areas,such as energy storage materials,hydrogen storage materials,flame retardant materials,superconductivity,heterogeneous catalysis and enxironmental protection and so on.Nowadays,Oxides compounds of V2O5.MoO3 and SnO2 have become the hotspots in the research of nanomaterials.In this paper,we have synthesized nanomaterials of V2O5 nanobelts,TiO2 doping V2O5 nanobelts.MoO3 nanobelts,Graphene/SnO2 with frequently used chemical synthesis methods,hydrothermal,sol-gel,low-tempeture calcined and water bath.The influences of synthetic parameters on morphologies and crystal structure,such as,reaction time,reaction tempeture.reaction media and doping amount,have been investigated.The growth mechanism of nanomaterials has been discussed.The main results are as follows:(1)Orthorhombic V2O5 single-crystalline nanobelts have been synthesized by 180 ? hydrothermal treating V2O5·nH2O precipitate derived from aqueous solution of V2O5 and H2O.The V2O5 single-crystalline nanobelts are several tens of micrometers in lengths.30-80 nm in width,30-40 nm in thickness.The surface of nanobelts is smooth.V2O5/TiO2 nanocomposites have been fabricated using orthorhombic V2O5 nanobelts and tetraburyl titanate as reactant by sol-gel.The influences of TiO2 doping amount and calcined temperature on the nanocomposites have been investigated.The results shows that the structure of nanobelts will not be destroyed by calcined temperature.When the tempeture is 300 ?,Ti02 is still amorphous;400 ?,the surface of nanobelts are covered by uniform TiO2 nanoparticals;500 ?,the diameter of TiO2 nanoparticals increase significantly.The cyclic voltammograms tests indicate that the V2O5/TiO2(molar ratio V:Ti=10%)nanobelts have better electrochemical properties and stable structure than other ratios(5%,20%).So we can draw a conclusion that V2O5/TiO2 nanocomposites are the best materials after sintering at 400? for 1 h with molar ratio 10%.(2)MoO3 nanobelts have been synthesized by a facile water bath at 90 ? without any surfactants and templates between Mo power and H2O2.MoO3 nanobelts are several tens of micrometers in lengths,80-100 nm in width,20 nm in thickness.The reaction time results show that MoO3 nanobelts are changed from MoO3·H2O nanobelts with dehydration.MoO3 nanobelts are also obtained when the media is transformed into C2H5OH.the difference is the formation mechanism compared with H2O.In acidic environment,the influences of different dianions on MoO3 nanobelts have been investigated.In the presence of Cl-,MoO3 nanobelts are several tens of micrometers in lengths;but in the presence of NO3-,MoO3 nanobelts are several micrometers in lengths.MoO3 nanobelts obtained at 120 ? hydrothermal for 24h are alignment,divergence by the same vertices radially.At 180 ?,we get the single nanobelt which is about 5-10 ?m in lengths,100-200 nm in width.(3)Graphite oxide was prepared by the Hummers method from graphite,the graphite oxide was reduced by hydrazine hydrate,SnO2 nanoparticles were absorpted in the graphene.The ratio of graphite oxide and tin tetrachloride is 8:1,SnO2 nanoparticles are uniformly distributed in the graphene.The diameter of SnO2 nanoparticles is 4-8 nm.The formation of SnO2-graphene nanoparticles should not only reduce the degree of stacking of graphene sheets,but also boost the lithium storage capacity.In order to better coating,polyaniline were introduced.It is investigated from UV,IR spectrum that graphene is also layered structure and polyaniline polymerization in the layered structure surface.Graphene,polyaniline and SnO2 formed into sandwith layered structure.Electrochemical properties are improved due to the structure. |
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