| At present,graphene-based materials have been widely used in electrochemical sensing fileds due to their unique and superior physical and chemical properties.However,the irreversibly restacking of graphene sheets resulting from their strong interaction will reduce the effective surface area of the material and further affect its electrochemical sensing performance.In order to make full use of the sensing performance of graphene,it should be functionlized by some appropriate methods.For example,introducing new components and funcational groups in graphene,regulating the structure of grapheme material,as well as hybriding graphene with other funcational materials can effectively improve the performance of graphene.Moreover,the latest research shows that reducing the size of graphene sheets is more beneficial to improve its dispersion and electrochemical sensing performance.In this paper,the functionalization methods for graphene are firstly reviewed.Based on this,a small-sized reduced graphene oxide–multi walled carbon nanotubes composite?rGO-MWCNTs?has been prepared.Furthermore,some metal nanoparticles have been introduced in this rGO-MWCNTs and the MNPs-rGO-MWCNTs composite have been obtained.These composite have also been used for the electrochemical sensing for phenol,hydrazine,p-nitrophenol and glucose,respectively.The main contents of this paper are as follows:1.A small sized reduced graphene oxide-multi-walled carbon nanotubes composite?rGO-MWCNTs?was prepared by one-step chemical reduction method in ethylene glycol?EG?.The morphology of rGO-MWCNTs composite was studied using scanning electron microscopy?SEM?.The electrochemical behavior of phenol on this rGO-MWCNTs composite modified glassy carbon electrde was also investigated carefully.The results showed that MWCNTs inserted into the rGO lamellae and improved the dispersion of rGO.On the other hand,the small sized rGO was conductive to the exposure of MWCNTs.Moreover,under the action of the skeleton of MWCNTs,the rGO sheets also formed a more three-dimentional structure,which effectively increased the specific surface of the composite.This modified electrode exhibited high electrochemical activity for the oxidation of phenol.Under the optimum conditions,the linear range for the determination of phenol with DPV in 0.01 mol?L-1 sodium tetraborate solution was 1.0×10-71.0×10-4 mol·L-1.The detection limit was 3.2×10-8mol·L-1?3sb?.2.A platinum nanoparticles-rGO-MWCNTs?PtNPs-rGO-MWCNTs?composite was prepared using one-step chemical reduction method in EG by adding precious metal Pt into the system and drooped on the surface of glassy carbon electrode.The morphology and the electrochemical activity of this PtNPs-rGO-MWCNTs composite were also studie carefully.The results showed that this rGO-MWCNTs composite had larger specific area and more active sites,which could be used as a good carrier for highly reactive loaded PtNPs.This PtNPs-rGO-MWCNTs exhibited high electrochemical activity for the oxidation of hydrazine under the synergic action of the components in composite.Under the optimized conditions,the linear range for the detection of hydrazine in phosphate buffer?pH 7.0?by amperometric method was 2.0×10-72.3×10-3 mol·L-1,the detection limit was 45 nM?3sb?,and the sensitivity was 219.7?A·(mmol·L-1)-1.3.A ZnO-rGO-MWCNTs composite was prepared by solvent heat method.adding ZnO to the above system.The morphology and the electrochemical activity for4-nitrophenol?4-NP?of this composite were studied using scanning electron microscopy?SEM?and electrochemical techniques.The results showed that this rGO-MWCNTs composite could be used as a good carrier for obtaining ZnO with small particle size and good dipersion.The electrode exhibited high electrochemical activity for 4-NP under the synergic action of the components in composite.In 0.1 mol·L-1 phosphate buffer?pH7.0?,the linear range for the determination of 4-NP with first derivative voltammetry was in the range of 5.0×10-75.0×10-55 mol·L-1.The detection limit was 1.0×10-7mol·L-1?3sb?.4.A PdAu-rGO-MWCNTs composite modified glassy carbon electrode?PdAu-rGO-MWCNTs/GCE?was fabricated using two-step method.Firstly,rGO-MWCNTs were introduced on GCE by drooping method.Then,Au-Pd bimetal nanoparticles were electrochemically deposited on the surface of rGO-MWCNTs from a solution containing chloroauric acid and potassium chloropalladate.Benifiting from the good carrier function of the rGO-MWCNTs,the high electrochemical catalytic activity of Pd-Au bimetals,this PdAu-rGO-MWCNTs/GCE showed high electrochemical activity for the electrode process of the oxidation of glucose.Under the optimized conditions,the linear range of glucose with first derivative voltammetry in 0.10 mol·L-1 NaOH was 2.0×10-54.0×10-4 mol·L-11 and 4.0×10-41.0×10-2 mol·L-1 with the detection limit of 1.0×10-5 mol·L-1?3sb?. |
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