Sythesis Of Porous Micro/nano Composites Derived From Zn-MOF,Co-MOF And Their Applications In Energy Storage And Conversion

With the rapid development of economy and industry,environmental pollution and energy crisis are becoming more and more serious.How to produce and utilize renewable energy more effectively and stably has become an urgent issue for human beings.The key to efficient use of new energy sources is the storage and conversion of energy.The performance of these devices is highly dependent on the nature of their electrode materials,and the further breakthroughs in materials will be crucial to the development of next-generation's energy storage and conversion.In recent years,the application of metal-organic-frameworks(MOFs)in electrochemistry has attracted people's attention because their compositions and mechanism adjustability allow people to tune at the molecular level according to the target performance.Meanwhile,the MOF's ordered well-defined pore structure facilitates rapid mass transfer in structure.Due to these unique advantages,MOFs can be used as a sacrificial template to prepare various nanostructured materials through different treatment methods,which can be used in energy storage and conversion.The research content of this thesis is as follows:(1)A high-N content doping hierarchical porous carbon nanorod composite H-N-C derived from MOF was prepared and used as a supercapacitor cathode material.The carbonization of MOF is carried out in twice,and a new N-containing ligand is introduced to the first carbonization product between two steps to form a hierarchical dual-ligands Zn-MOFs,followed by high-temperature calcination to obtain a high N content porous carbon nanorods.We adjust the reaction time and temperature to facilitate the pore structure,the N content of the product,and the specific capacitance and stability of the material.As the prepared electrode material exhibites a specific capacity of 162 F/g at a current density of 1.25 A/g,and the capacity was not attenuated after 10000 cycles at a high current density of 20 A/g,showing excellent cycle stability..(2)A novel hollow core-shell structured Co2P@C sphere derived from Co-MOF was synthesized and employed as an OER catalyst.The Co2P@C hollow sphere were successfully prepared by simultaneous phosphating and heat treatment of the precursors by using the Co-based MOF materials.The sample DCo-P-450-2 with high catalytic performance was obtained through controlling the pyrolysis step,phosphating temperature and heating rate.As the OER catalyst,the overpotential at a current density of 10 mA/cm2 is 330 mV,the Tafel slope is only 44 mV/dec,and it exhibits excellent stability.