Microwave Combustion For Preparation Of Graphene Based Composite And Application Of Electrochemistry

Recently,with the socio-economic development and population growth,energy shortages and environment deterioration have become global problems.To address energy shortage,the development of new energy,energy conversion and storage technology has become important research.Because of the economic,practical,green and other characteristics in energy conversion and storage utilization,electrochemical technology has a wide range of applications.Electrode material is the core of electrochemical applications,electrode material preparation and modification is the key to the impact of electrochemical performance.The traditional electrode material preparation and modification methods have shortcomings such as harsh conditions,long time-consuming and limited application scope.It can't meet the current electrochemical research.Therefore,microwave principle of some new methods gradually applied to the electrode materials.However,the current microwave method has not yet formed a complete material preparation and modification system.In this paper,microwave and graphene oxide are combined to form a kind of universal method for preparing and modifying electrode materials,namely microwave combustion.In this paper,the applications of transition metal oxides,elemental and carbides prepared and modified by microwave combustion in supercapacitors and electrocatalysis were studied in detail.The main results are following:(1)A variety of transition metal oxides and graphene composites with oxygen vacancies were successfully fabricated by microwave combustion.Niobium pentoxide and graphene composites synthesised via microwave combustion by the introduction of oxygen vacancy,successfully solved the problem of poor conductivity of niobium pentoxide.Using this composite material as a supercapacitor electrode for organic electrolyte testing,we found that the 2 m V/s sweep speed its specific capacity can reach close to the theoretical value of 726.2 C/g,while it also has very good cycle stability and nearly 100%coulomb efficiency.The specific capacitance of manganese dioxide nanoparticles and porous graphene composites prepared by microwave combustion in the two-electrode system of acid solution reached 71.1 F/g at a speed of 2 mV/s,and also showed excellent electrochemical performance.(2)A variety of transition metal elements and graphene composites were successfully prepared by microwave combustion.With deepening the microwave action,the transition metal element will be generated.The complex of platinum nanoparticles and porous graphene were prepared by one step method after the treatment with chloroplatinic acid.The results show that the Tafel value of the hydrogen evolution reaction in the acidic solution is 35 mVdec-1,and the number of transfer electrons in the oxygen reduction reaction is 3.94,which shows excellent electrocatalytic performance.The preparation of silver nanoparticles and graphene composites,due to their different sizes of uniform composite,but also in different applications have a good prospect.(3)A variety of transition metal carbides and graphene composites were successfully prepared by microwave combustion with universal properties.With the deepening of the degree of reaction,the transition metal oxide will be reduced to metal elements,and then react with carbon to generate carbides.In order to study the effect of electrocatalytic hydrogen evolution,the different sizes of nitrogen and cobalt doped porous molybdenum carbide were prepared to show that different nanocrystallization and doping processes had an important effect on electrocatalysis.When the tungsten carbide nanoparticles and graphene composites were prepared as the electrocatalytic electrode,the Tafel values in the acid-base were 43 mVdec-1 and 59 mVdec-1,showing excellent catalytic activity.