Synthesis Of Cellulose-based Carbon Spheres And Its Application In Cyclohexene Oxidation And Capacitors

Owing to the continuous consumption of non-renewable resources,the researches for renewable resources are increasing continuously.Among them,the most researched renewable resources are biomass materials.Cellulose,as the most abundant renewable resource and biomass material in nature,had not been fully utilized.Such materials are often directly burned directly as fuel,causing serious environmental pollution.Because of the unique structure of cellulose,how to make full use of cellulose has been a hot research field.Based on the characteristics of cellulose structure,in this dissertation,cellulose was firstly degraded by using various Fe species as catalysts via hydrothermal reaction.Then,the resultant degradation products were used as precursors to fabricate a series of carbon spheres with/without hollow structures.Finally,the applications of carbon spheres as catalyst carrier or capacitor device were investigated.The main contents were as follows:?1?Using ferrous ammonium sulfate hexahydrate as a catalyst,the cellulose was hydrothermally degraded,successively,the resultant degradation products were used as precursors to fabricate carbon spheres with hollow structure.By optimizing the fabricating conditions,the carbon spheres with hollow structure were synthesized?the optimal conditions:water volume 100 mL;mass ratio of carbon precursor to Fe species 1:1;pH=1;hydrothermal time 2 d;carbonization temperature700°C?.The hollow carbon spheres were used to support Au nanoparticles?AuNPs?,yielding a series of AuNP-C composite catalysts.In cyclohexene oxidation reaction,the optimal catalyst of Au-C-100?H₂O?-1:1-pH1-2d-700-1%showed good catalytic performance.The conversion rate of cyclohexene and the selectivity of C6 were 52.7and 87.5%,respectively,while the TOF value was as high as 746 h^-1.In addition,the catalyst could be reused for 3 times without significant loss of catalytic activity.?2?Using ferric chloride hexahydrate as a catalyst,the cellulose was hydrothermally degraded,and the degradation products were characterized by MS and FT-IR.Solid carbon spheres were synthesized by using the degradation products as carbon precursor via a soft template method.The resultant carbon spheres were characterized by TEM and nitrogen adsorption/desorption,and subjected to electrochemical test.It was found that the activated carbon spheres had a BET surface area as high as 1065 m²/g with pore volume of 0.31 cm³/g.In the capacitor specific capacitance test,the specific capacitances of unactivated and activated carbon spheres were 92.6 and 149.5 F/g,respectively.