| Micro/nano structure cuprous oxide as a p-type semiconductor can be applied in photocatalysis,the photolysis of water,solar cells,biosensor,sterilization.Micro/nano structure Cu2O with different morphology and size shown highly improved physical and chemical properties.It has great practical significance that realize the effective control of crystal structure parameter of size and morphology.In this paper,gallic acid was used as green reductant to synthesis of micro/nano structure Cu2O by liquid phase reduction method.Meanwhile Stannic oxide with high theoretical specific capacity can be applied in lithium ion batteries.In order to eliminate pulverization phenomenon and volume effect in the process of circulation,the synthesis of SnO2/C composites to slow its volume effect to improve the electrochemical cycle performance.In this paper,we prepared the micro/nano cuprous oxide crystal particles by liquid phase reduction method with gallic acid as reducing agent,and studied pH value,the initial material ratio of Cu2+:GA,mixing way,reaction time,and additive PVP conditions on the effect of Cu2O particles.Then the micro/nano Cu2O crystal growth mechanism and electrochemical performance were explored.We synthesize SnO2/C composite material by hydrothermal synthesis method with Vc as a carbon source,and study the pH value,initial material ratio(Sn2+:Vc),reaction temperature,reaction time on the influence of morphology and phase of SnO2/C.Finally their electrochemical performance was test.The research results show that pH value has a great influence on the morphology of Cu2O crystal.The morphology of Cu2O exhibits irregular at pH=9;Cu2O is rod at pH=10,Cu2O particles exhibit cubic shape at pH=11;When the pH value increases to 11.5,Cu2O particles change into tetrakaidecahedron.In the process of titration the transformation solution pH also has significant effect on the morphology of reaction product.Adjusting pH value to 11 at the end of the titration,reaction product obtained is Cu2O of spherical morphology or octahedral with paticle size 100 nm,and adjusting pH in the reaction process to keep pH in 11,reaction product exhibit cubic shape particles.The initial material concentration ratio has a great influence on morphology of Cu2O.In the pH=10,with the increase of proportion of gallic acid,length of Cu2O rods grow longer.When ratio of Cu2+:GA reaches 1:1,Cu2O change into nano-polyhedron.The order of the titration and reaction time have effects on morphology of Cu2O particle.Dispersion of reaction product prepared by reverse titration is good,and the agglomeration and twin phenomenon decreases.Conversely,dispersion of the reaction product prepared by positive titration is poor.With the extension of reaction time,the rough polycrystalline rod of Cu2O change into smooth single crystal rod in the pH=10.With the extension of reaction time,cubic Cu2O didn’t change at pH=11.And when the time reach 8 h,product exhibit impurity phase of CuO.When adding 1.8g PVP(8000),Cu2O change from cubic into tetrakaidecahedron.When adding 1.2g PVP(30000),the shape of Cu2O change from cube into tetrakaidecahedron.Electrochemical analysis show that cycle performance of cubic Cu2O is better than cycle performance of liner Cu2O.After 20 times circulation,the specific capacity of cubic Cu2O is 109.3 mAh/g and specific Capacity of the linear Cu2O is 55 mAh/g.SnO2/C composite material was prepared by hydrothermal with Vc as carbon source for the first time.With increasing pH value,the grain size of carbon decreases and the agglomeration degree improve.With the increase of temperature,grain size increases and the spherical carbon produce spherical diameter.Wth the ratio of Sn2+increases,the shape of the amorphous carbon changes from spherical shape to random shape and grain size decrease.Electrochemical analysis show that the cycle performance of SnO2/C composite material under hydrothermal condition of the intial material ratio of Sn2+:Vc=1:2 is best,specific capacity is 191.3 mAh/g after 10 times cycle. |
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