Synthesis Of Porous Carbon Spheres By Domain-limited Pyrolysis Approach And Their Characteristic And Application

With the rapid development of national economy,problems such as air pollution and energy shortage are becoming more and more serious.In order to solve the above problems,it is urgent to develop a new adsorption and energy storage material with good performance.In recent years,porous carbon materials have attracted great interest among researchers due to their high surface area,abundant porous structure,as well as excellent conductivity and stability.The main factors affecting the properties of porous carbon are the porous structure and material composition.Therefore,the exploration of adjusting the porous structure and material composition of porous carbon materials to effectively improve performance of adsorption and energy store is essential by controlling reaction conditions.The work is as follows:（1）In this work,we reported a domain-limited carbonization approach for the easy synthesis of the yolk-shell C@Si O₂ spheres using resorcinol-formaldehyde（RF）resin as carbon precursor and outer compact silica shell as a confined nanospace.The porous structure of C@Si O₂ spheres can be easily controlled,by simply modifying the carbonization temperature,heating rate and size of RF@Si O₂ spheres.The obtained C@Si O₂ spheres had high surface areas（238.5-732.5 m²/g）,large pore volume（0.111-0.647 cm³/g）and abundant micro-mesoporous structure.Subsequently,a series of C@Si O₂ spheres were evaluated for toluene adsorption.Among them,the S-C@Si O₂-400 spheres had adsorption capacity of 448.2 mg/g for toluene,which increased by88.73%compared with the ordinary carbon spheres.This was mainly attributed to its largest specific surface area（732.5m²/g）and abundant mesoporous carbon slice structure.Meantime,the factors that affected the formation of these spheres were also studied,while the adsorption capacity was positively correlated with the mesoporous pore volume.（2）The N-doping yolk-shell carbon spheres with a“carbon bridges”structure were synthesized using resorcinol-formaldehyde（RF）resin as carbon precursor,ethanediamine as nitrogen precursor and outer compact silica shell as a confined nanospace.The“carbon bridges”structure was created based on the swelling-shrinkage of RF spheres during the carbonization process.The“carbon bridges”structure between carbon core and carbon shell formed a highly conductive network.Moreover,the structure of the“carbon bridges”structure and the thickness of the carbon shell can be adjusted by controlling the thickness of the silica layer,leading to a change in morphology,namely from dense spheres to complete yolk-shell spheres.The results disclosed that the obtained yolk-shell C@C-2 spheres as an electrode material for supercapacitors exhibited a reversible specific capacitance of 373.3 F g^-1 at 0.5 A g^-1 in2 M KOH and retained a well-advanced capacitance retention capability（95.8%）at 4A g^-1 for more than 10000 cycles.