Study On Preparation Of Ultrathin Silver Nanowires And Its Applications On Electrocatalysis And Supercapacitors

As the consequence of their unique optical,mechanical,electrical,and thermal properties,silver nanowires and its composites have exhibited important applications in various fields such as flexible transparent conductive films,catalysts,sensors,as well as energy conversion and storage and so on.Therefore great attentions have been focused on the preparation of silver nanowires and exploitation of their applications.Herein,the main content of this thesis is the preparation of ultrathin silver nanowires and composites and its applications on electrochemical reduction of carbon dioxide（CO₂）and supercapacitors.The main results obtained are as follows:（1）Preparation of ultrathin silver nanowiresThe large scale synthesis of silver nanowires with an average diameter of 30 nm and an aspect ratio larger than 1000 were carried out by using ethylene glycol（EG）and diethylene glycol（DG）as co-mediated solvents in the presence of poly（vinyl pyrrolidone）（PVP）and nucleant（NaCl and KBr）through one-pot polyol method.As the same time,with different polyols such as EG,DG,TG（triethylene glycol）and a mixture of both used as reducing agents and solvents,the effects of different reduction ability and viscosity of different polyols on the final morphologies of silver nanostructures have been discussed.（2）Silver nanowires as supportless electrocatalysts for electrochemical reduction of CO₂The synthesized silver nanowires have been investigated as supportless electrocatalysts for electrochemical reduction of CO₂.Experimental results revealed that silver nanowires as electrocatalysts is capable of electrochemically reducing CO₂ to carbon monoxide（CO）with approximately 80% catalytic selectivity at-0.9V vs.RHE（reversible hydrogen electrode）.（3）Silver nanowires and Mn3O4 core-shell nanocomposites as the electrode materials for supercapacitorsOne-Dimensional silver nanowires and Mn3O4 core-shell nanocomposites were successfully prepared by a simple chemical synthesis method and used as the electrode materials for supercapacitors.The novel electrode materials exhibited a high specific capacitance(200.7 F g^-1 at the scan rate of 5 mV s-1 and 203.0 F g^-1 at the current density of0.25 A g^-1)and desirable cycle stability(73.8% of the capacitance can be retained after 3000 cycles at 1 A g^-1)in 0.5M Na₂SO₄ aqueous solution.