The Study Of Preparation,Mechanism And Electrocatalytic Properties Of Ultra-Long Copper Nanowires

Copper nanowires,due to its high aspect ratio,can exhibit excellent properties and promising applications such as electronics and catalysis.Recently,domestic and foreign researchers carried out some exploratory work on the preparation,properties and application of Cu nanowires,but few about the mechanism.In this paper,we got an optimum condition through hydrothermal method to prepare Cu nanowires,after systematically studied the copper nanowires obtained from different experimental conditions,then we analyzed and studied the Cu nanowires synthesis process and growth mechanism through analyzed the intermediates of different stage and alkylamines.At last,the uniform,long thin copper nanowires were used to prepared copper film electrode,and we studied the performance of the copper film electrode on electric catalytic reduction of nitrate.The main conclusions are drawn from this work as follows:Firstly,in hydrothermal synthesis of system,the phase composition and morphology of the copper products are closely related with reaction temperature,reaction time,mole ratio of reactants,kinds of solvent,value of pH and valence states of copper source.High temperature can make the copper nanowires growth too fast,leading to the decrease of aspect ratio and disorder.But too low reaction temperature or too short reaction time cannot acquire pure product.Besides,mole ratio of reactants,solvent type and value of pH all has important influence on the morphology and phase.We found the optimum preparation condition to prepared copper nanowires with length reaches more than 3 mm:CuCl₂22H₂O as source of copper,deionized water as solvent,oleyamine and CuCl₂22H₂O feeding molar ratio is 4:1,under the condition of natural acidity,160?for 96 h.Secondly,through MS,IR,XPS,SAXRD and TEM characterization methods,we found oleylamine play as reducing agent,stabilizer and dentate template etc multiple effect.In the reduction process,oleyamine molecules and copper chloride formed a kind of complex:CuCl₂[[C₈H₁₇-CH=CH-?CH₂?₈]₂-NH],then the complex absorbed more oleyamine molecule to form more complex compound.These complex compounds played as template,and then decompose to[C₈H₁₇-CH=CH-?CH₂?₈]₂-NH as a by-product.What's more,the by-product can form a kind of mesoporous structure,then Cu²⁺and Cu⁺in situ reduced to the zero valence in the mesoporous structure.Due to the limitation of the template and mesoporous,copper atoms gather together to grow into long copper nanowires.Thirdly,the first time to prepared film electrode of ultra-long copper nanowires,and the film electrode shows excellent catalytic performance in the reduction of nitrate ion process.The roasting temperature has a significant effect on the final electrode structure and performance,in the process of preparation.The results of our study demonstrate that thin film electrode obtained by the calcination temperature of400?can electric catalytic reduction of nitrate ion in a relatively low potential,and has a good anti-jamming ability to Cl^-,HCO^3-,HPO₄^2–and H₂PO^4-.The optimal value of pH was two,under which the film copper nanowires electrode can show the best electric catalytic activity to reduction of nitrate ions.The results of research show that the electrochemical reduction of nitrate ions at the surface of copper electrode is controlled by mixed diffusion and adsorption mechanism.