Study On The Preparation Of 3D Carbon Nanomaterials Derived From Zeolitic Imidazolate Frameworks And Their Applications In Environmental Electrochemistry

In order to promote sustainable development,green and renewable clean energy and environmental technologies continue to be developed to meet the growing demand for energy and the environment,such as fuel cells,hydrogen peroxide sensor and super capacitor.It is urgent to develop appropriate nano materials for these energy and environmental technologies to reduce the volume of the device,improve the efficiency of energy conversion as well as the accuracy.In this thesis,a series of carbon nano electrodes were designed and developed on the basis of new type of ZIFs based carbon nanomaterials.The morphology and structure of the electrode materials were investigated,and the relationship between the electode materials and electrochemical properties was studied.The potential applications of ZIFs based carbon nanomaterials in energy and environment were expounded.Specifically the following three aspects:(1)Co,Ni and N tri-doped carbon nanomaterials based on ZIF-67 were designed and synthesized through the introduction of nickel containing coordination compounds into ZIF-67.The materials showed coral or spongy microstructure,ZIF-67 discrete particles combined together,providing rich microporosity and high pyridine nitrogen content,and forming Co-N-C and Ni-N-C as active sites.The materials as ORR and OER electrodes in acidic and alkaline conditions showed a very strong activity with an over potential between EOER and EORR of 0.78 V.The bifunction performance of ORR and OER of our materials are higher than that of commercial Pt/C and that of most noble metal free catalysts.(2)Boron doped sandwich structural ZIF-67 based carbon nanomaterial was designed and synthesized by compositing ZIF-67 with graphene,and doped boron atom through CVD method.The new material can form new active sites like BNC bonds and Co2B bond,and increase the pyridine nitrogen content.The material was used as electrode to detect H2O2,and exhibited the outstanding performance:linear response range 0.5 M?60 mM,detection limit as low as 0.19 M,and response time less than 3 s.The linear error of detection range in the low concentration region(<0.5 mM)and high concentration area(>0.5 mM)can both reach up to 0.999.The performance of our material is better than that of the similar carbon materials reported at present.(3)ZIF-7 carbon aerogels composites were designed and synthesized through the introduction of ZIFs into the carbon aerogels.The obtained carbonized materials showed the microstructure of ZIF-7 coated chitosan fibers.This structure can accelerate the transmission of electrons in one direction,so that the internal resistance is reduced.The material was used as the electrode material in supercapacitor,which showed a specific capacitance of 173.1 F g-1 and internal resistance of 2 ?,much better than that of the carbonized ZIF-7 electrode material.