Preparation Of Various Carbon-carbon Nanohybrids Modified Electrodes And Their Applications In Environmental And Biosensing

Organic pollutants are chemicals compounds of global concern due to their potential for longrange transport,persistence in the environment,ability to bio-magnify and bio-accumulate in ecosystems,as well as their significant negative effects on human health and the environment.On other hand,the abnormal number of biomolecules in humans can cause various diseases to offer serious effects to human health and even results the death of human.Thus,developing effective method to detect organic pollutants and biomolecules is very important.Owing to the inherent advantages such as high sensitivity,specificity,real-time output,low operating cost,and potential for the miniaturization and portable instrumentation,electrochemical methods aroused wide attention and have important applications in sensing organic pollutants and biomolecules.During the last decade,various carbon-based nanomaterials such as graphene,carbon black(CB),carbon nanotubes(CNTs)and carbon nanohorns(CNHs)have attracted significant interest of researchers in electrochemical sensors due to their excellent biocompatibility and electrochemical catalytic activity.In this thesis,by choosing three typical pollutants(hydroquinone(HQ),paracetamol(PCM),para-chloronitrobenzene(PCNB))and one biomolecule(dopamine)as models,we designed different electrochemical sensors for organic pollutants determination and biomolecules by using carbon-carbon nanohybrids modified glassy carbon electrodes as follow:(1)By using wet chemical method via a simple and green ultrasonication process,a novel tree dimensional nanohybrid composed of CNHs and CNTs was prepared successfully.The sensor based on CNHs/CNTs modified electrodes for electrochemical detection of PCNB was fabricated and under optimized conditions,the result showed that the obtained 3D CNHs-CNTs nanohybrids could exhibit electrochemical sensing performances toward PCNB detection due to the synergetic properties from CNHs and CNTs,and a wide linear range from 0.1 to 70.0 mM coupled with a low detection limit of 5.9 n M were obtained for the determination of PCNB and the recoveries were 97.3%~101.5% in real samples.(2)We constructed an electrochemical sensor for simultaneous determination of HQ and PCM by using Nitrogen-doped carbon layer-coated CB wrapped with reduced graphene oxide(NCB/r GO)novel nanohyrids.The composite was prepared by polymerizing the dopamine hydrochloride(DA)on CB surface and subsequently a simple self-assemble process between graphene oxide(GO,negative)and polydopamine(PDA,positive),follow by carbonization and reduction procedures at high temperature.Various technologies including transmission electron microscopy,scanning electron microscopy,X-ray diffraction,Raman spectroscopy and electrochemical method were used to characterize NCB/r GO.After optimizing the detection conditions,the analytical responses of NCB/r GO modified electrode has a linear range between0.05 and 20.0 ?M for both targets with low detection limit(0.0165 ?M for HQ and 0.0262 ?M for PCM).(3)Through a simple wet chemical method,the composite nanomaterial was synthesized by self-assembly of amorphous CB and CNHs.The composite was characterized by different techniques including the scanning electron microscopy,transmission electron microscopy and Raman spectroscopy.The sensor based on CNHs/CB modified glassy carbon electrodes for electrochemical determination of dopamine was constructed.Under optimized conditions,the result show that the concentration of dopamine had good relationship with peak current in linear range between 0.05~20.0 ?M,and the detection limit 0.013?M.