Dimensional Carbon Materials And Their Functional Applications In Electrochemistry

Due to good mechanical, electrical and chemical properties, carbon materials havebeen widely researched. Especially in electrochemical fields, carbon materials have theirown advantages. Carbon materials with different dimensions show diferent electrochemicalproperties. With unique two dimension structure, graphene has large theoretical specificarea, excellent electrical conductivity, outstanding chemical stability and plasticity, basedon which graphene is widely investigated in electrochemical fields. Carbon nanotube withone dimension structure also expresses advantage in electrochemical fields. This thesismainly focuses on the preparation of dimensional carbon functional composite and theirelectrochemical applications.First, we prepared graphene composite Fe-C-N as electrochemical oxygen reductionreaction (ORR) catalyst with the precursor of graphene oxide, cyanamide and ferric nitrate.The results showed that the addition of iron salt promotes the formation of ORR active site.Meanwhile, cyanamide was able to create porous structure in Fe-C-N composite.Importantly, Fe-C-N exhibited outstanding ORR activity in both alkaline solution andneutral solution. Further, we fabricated a methylene blue fuel cell with Fe-C-N as cathode.The cell could generate electricity and remove methylene blue. At the current of81μA cm-2,the maximum power densities could achieve7.3μW cm-2.Then, we fabricated graphene-carbon nanotube composite through one-pot annealingstrategy and investigated its application in electrochemical supercapacitor. Graphene andcarbon nanotube in the composite crosses each other, displaying perfect dispersion incounterpart. The specific surface area was903m2g-1. The electrochemical investigationdemonstrated that graphene-carbon nanotube prepared in our one-pot annealing strategyexhibits excellent supercapacitor performance. The synergistic effect between graphene andcarbon nanotube is benefit for the supercapacitor performance of graphene-carbon nanotubecomposite. On the other hand, the length of carbon nanotube can be adjusted throughvarying the ratio of precursors, and the lenghth of carbon nanotube also has effect on theirsupercapacitor performance. The maximum specific capacitance can achieve413F g-1. Unique3D structure endows graphene-carbon nanotube composite perfect durability. At thecurrent of1A g-1, the specific capacitance of GN-CNT6.0increased to115%compared to itsinitial value.We also design and prepared3D porous structured graphene through sponge-templatedstrategy and explore its potential application in capacitive deionization (CDI).The obtainedgraphene materials displays porous structure and the specific surface area was305m2g-1,higher than that of graphene prepared without the help of sponge. The pore size distributionis from3.5nm to89.9μm. In20mL106μS cm-1NaCl solution, with flow rate of3mLmin-1and1.5V applied voltage, the prepared graphene can achieve4.95mg g-1electrosorptive capacity. Meanwhile, the prepared3D graphene materials exhibits a fastdesorption rate of25mins.Finally, we synthesize one-dimension carbon nanotube-copper oxide composite, andapplied it in the fabrication of electrochemical glucose sensor. With the help of surfactant,we have successfully obtained carbon nanotube decorated with copper oxide nanoleaves,which possess desirable electrochemical glucose sensing performance. The sensitivitytoward glucose is664.3mA mM-1cm-2and the detection limit can achieve5.7μM.