Preparation Of Metal Nanostructures And Construction Of All-carbon Battery Based On Galvanic-cell Mechanism Of Surface Functional Groups On Monolithic Activated Carbon(MAC)

Activated carbon is a kind of carbon materials with rich pore structures.Of which,Monolithic activated carbon(MAC)has more advantages due to its tunable shape,high bulk density,high density and much larger surface area per unit volume,and also easiness to store and transport.Our research group has developed a novel type of MAC with rich surface functional groups,huge specific surface area and high electrical conductivity,which may make surface functional groups being able to become energy carrier and convert chemical energy into the form of electricity.In this work,we propose a new “galvanic-cell mechanism of surface functional groups on MAC” based on experimental results and investigated the growth and preparation of nano-metal with special structures.Chemical energy stored by surface functional groups on MAC can be transformed into electricity via galvanic-cell mechanism.Under the framework of this mechanism,the shape of the nano-metal is also tunable by bringing about morphosynthesis in the preparation system to achieve silver nanocage.Further the reduction through galvanic-cell mechanism is extended to prepare other metals or metal oxides.Cuprous oxide nanocube and seaweed-like copper oxide structure are obtained.In the end,the concept of all-carbon battery is proposed based on the similarity between galvanic-cell mechanism and fuel battery,and study of its feasibility is made.Specifically,chapter one reviews the current application situation of surface functional groups on different materials,and introduces the characterization methods of surface functional groups and also the preparation and application of activated carbon.Then chapter one resumes the proposal of “galvanic-cell mechanism of surface functional groups on MAC”,together with its verification,morphological control,extension,and application on designing novel all-carbon batteryIn chapter two,we find out that dendritic silver nano-structure can be obtained while immersing MAC in silver nitrate solution without the addition of any other chemical agent.Characterization of surface functional groups on MAC and analysis of the growth process of dendritic silver by setting a series of experiments indicate that charge transfer occurs along with the preparation of silver nano-structure.The “galvanic-cell mechanism of surface functional groups on MAC” is firstly proposed.In chapter three,cubic silver nanocage is prepared by the introduction of silver insoluble salts as templates by absorbing anions in prior,in order to verify the galvanic-cell mechanism.Microporous structure of MAC can help the formation of silver insoluble salt with special morphology.The followed gradual-reduction of the templates and the formation of cage-like structure are both the evidences of the “galvanic-cell mechanism of surface functional groups on MAC”.This phenomenon also proves that the morphologies of metal nano-structures prepared on MAC can be tuned by different methods through the same galvanic-cell mechanism.In chapter four,the reducing ability of surface functional groups on MAC applying to other metal ions of different types is discussed.Results show that gold and platinum ions are reduced to single metallic state in different shapes,while zinc,lead,nickel,cadmium,iron,chromium and manganese are mainly adsorbed by MAC forming oxides with different morphologies.Cuprous oxide nanocube reducing from divalent copper ions on the surface of MAC is studied in detail.The result can not only be used to evaluate the reduction activation of surface functional groups on MAC,but also indicate the potential application of the “galvanic-cell mechanism of surface functional groups on MAC” on preparing multiple metal or metal oxides in different shapes.Baced on the galvanic-cell mechanism which is essentially the chemical energy storing and electrochemical converting mechanism,a new concept of all-carbon battery is built.All-carbon battery device is formed by two MAC electrodes treated by different modifications such as acid/ alkali soaking,MAC carbon skeleton which has good electrical conductivity,and electrolyte.The two poles are rich in oxidizing groups and reducing groups respectively.The same set of oxidation and reduction reactions takes place on both electrodes,which is proved by electrochemical characterization of positive and negative electrodes.Surface functional groups consumed in electrochemical reaction can be replenished through post-treatment regeneration(chemical treatment).Summary and prospect of this thesis are in chapter six.Future work is mainly as below: expanding the research of surface functional groups from MAC to more porous materials;developing the method of preparing micro/ nano metal/ metal oxides in special shapes using surface functional groups on porous materials to a simple,green,low cost system via the control of experimental parameters and introduction of other conditions;optimizing MAC parameters,such as types of surface functional groups,specific surface area,pore distribution,electrical conductivity,types and concentration of electrolyte etc,to improve the all-carbon battery’s energy density and power density.This thesis is expected to provide a new idea of application of surface functional groups on MAC,simple preparation methods of nano noble metals and metal oxides,and new-concept “green” energy.