Investigation Of Nanocomposites In Electrocatalysis And Energy Storage Applications

In the last few years,with the development of nanotechnology,nanocompositeshave attracted widespread attention due to their unique structure and special properties.Till now,nanocomposites have shown promising applications in the field of catalysis,photoelectricity and energy storage.Nanocomposites are able to complement the advantages of different materials,and result in some novel outstanding functions.Clearly,investigation of the preparation and application of nanocomposites have very important theoretical and practical values.In this study,we studied the preparation of two kinds of nanocomposites and their application in electrocatalysis and energy storage.The main contents are as follows:In the first chapter,we summarized the concepts,classifications,developing trends and application prospects of direct methanol fuel cell,supercapacitor and glucose sensor,focusing on the electrode materials and reaction mechanisms.Specially,we introduced the applications of nanomaterials based electrodes in the above mentioned field.In the second chapter,we prepared PtC nanocomposites and studied their application as electrocatalyst in direct methanol fuel cell.Firstly,we prepared carbon nanoparticles(CNS)with high surface area and excellent dispersion by calcining silk at high temperature.Ethylene glucol reduction method was employed to load Pt on the surface of CNS to form PtC nanocomposites.In this work,we mainly studied the electrocatalysis activity of the PtC nanocomposites modified electrode towards the electrooxidation of methanol and also its antipoisoning ability.The chemical characterization of the prepared PtC nanocomposites was performed by SEM,EDS,XPS and XRD etc.techniques.The results showed that Pt has been successfully modified onto the surface of CNS.Electrochemical methods,such as cyclic voltammetry and chronoaperometry,proved that PtC nanocomposites decorated electrode had high electrocatalytic activity towards methanol and super antipoisoning ability.In the third chapter,we prepared NiO-CdO nanocomposites by cation exchange process and studied their applications in supercapacitor and electrocatalysis of glucose.At first,Cd(NO3)2 reacted with urea to form CdCO3,which was transferred to porous Cdo after calcining at high temperature.After that,cation exchange between Ni2+ and CdO was employed to prepare NiO-CdO nanocomposites.In this work,NiO-CdO nanocomposites were applied in the field of supercapacitors and electrocatalysis of glucose.Cyclic voltammetry and galvanostatic techniques were used to investigate the electrochemical capacitor performance of NiO-CdO in terms of supercapacitors.The results showed that the specific capacitance of NiO-CdO reached 230 F/g under 5 mV/s scan rate,and the specific capacitance can remain 95.16%of the maximum value after continuous charge-discharge 1000 times,which indicates excellent cyclic stability.When applied in electrocatalysis of glucose,NiO-CdO nanocomposites modified electrode presented a wide linear response to glucose concentration(0.04-9.17 mmol/L),low detection limit(0.03mmol/L).Furthermore,it also showed satisfied performance in anti-interference and stability.