Electrochemical Performance Of Carbon Nanotubes@Mesoporous Carbon Three-dimensional Composites And Sensitive Detection Of Bisphenol A

The electrochemical applications of traditional carbon nanoma-terials such as carbon nanotubes?CNTs?and graphene?GR?powders are significantly impeded by their poor three-dimensional?3D?conductivity and lack of hierarchical porous structure.Here,we have constructed a 3D highly conductive CNTs networks and further combined it with mesoporous carbon?mC?for the creation of a core-shell structured composite sponge?CNT@mC sponge?that featured 3D conductivity and hierarchical porous structure.In the composite sponge,interconnected CNTs efficiently eliminates the contact resistance and the hierarchical pores significantly facilitate the mass transport.The combination of CNT@mC sponge and metal nanoparticles made the composite material have two functions,more conductive properties,higher selectivity,pertinence to the design of more targeted equipment.CNT@mC sponge exhibited high electron transfer rate,large electroactive surface area and excellent electrocatalytic performance in methanol fuel cells composed of carbon nanotubes@mesoporous carbon/palladium?CNT@mC/Pd?as a catalyst.In the electrochemical detection,the electrochemical sensor based on CNT@mC sponge showed a wide linear range and high sensitivity in the detection of environmental hormone bisphenol A.CNT@mC sponge aptasensor after function showed superior sensitivity in environmental hormone detection.Finally,the electrochemical performance of CNT@mC sponge was also investigated in impedimetric sensors.Good selectivity was obtained in impedimetric sensing of BPA.This study highlighted the exceptional electrochemical properties of the CNT@mC sponge enabled by 3D conductivity and hierarchical porous structure.The strategy described may further pave a way for the creation of novel functional materials through integrating multiple superior properties into a single nanostructure for future clean energy technologies and environmental monitoring systems.The main studies are as follows:1.Preparation and characterization of CNT@mC sponge:CNT@mC sponge was constructed and characterized by many characterization methods.Transmission electron microscopy?TEM?and scanning electron microscopy?SEM?images,we could clearly see the nanofiber structure and the mesoporous structure wrapped on the fiber.Due to the interconnection,the CNT@mC sponge processed high electron conductive path.There was a layered pore structure in the CNT@mC sponge from microporous to macroporous,which achieved efficient electron transfer?mass transfer?and minimal reactant diffusion distance.Nitrogen adsorption-desorption?BET?analysis showed that CNT@mC sponge had a larger specific surface area than CNTs.X-ray photoelectron spectroscopy?XPS?showed that CNT@mC sponge only contained C element.A series of tests proved that CNT@mC sponge showed a better electrochemical performance than CNTs and GR powders.The strategies described in this study may further pave a way for the creation of novel functional materials with multiple superior properties.2.Methanol fuel cell based on CNT@mC/Pd:In the DMFCs test,the palladium nanoparticles?Pd NPs?were reduced on the surface of CNT@mC sponges by electrodeposition to prepare CNT@mC/Pd.The CNT@m C/Pd modified glassy carbon electrode?GCE/CNT@mC/Pd?was prepared to catalyze the oxidation of methanol in alkaline medium.The cyclic voltammetry?CV??electrochemical impedance spectroscopy?EIS?and Amperometric i-t Curve?i-t?analysis showed that GCE/CNT@mC/Pd had a significant catalytic effect on methanol oxidation.Based on the CNT@mC/Pd half-cell reaction showed a higher and more stable effect than batteries based on other materials.3.Detection of BPA based on CNT@mC/Pt modified electrode:Based on the CNT@mC sponge substrate,the platinum nanoparticles?Pt NPs?was reduced using constant potential deposition method,and the CNT@mC/Pt modified glassy carbon electrode?GCE/CNT@mC/Pt?was prepared.The addition of nano-metal to CNT@mC improved the conductivity and electrochemical catalytic ability of the material,reduced the overpotential,increased the peak current.The CV?EIS?DPV and i-t showed that compared with GCE/Pt?GCE/CNT/Pt and GCE/G/Pt,which proved the superiority of GCE/CNT@mC/Pt.The electrochemical behavior of BPA on GCE/CNT@mC/Pt was studied,under the optimization conditions,the detection range was 1.0×10^-8 mol/L¹.0×10^-3 mol/L.The linearity equation was?_p??A?=5.94(c/mmol.L^-1)-0.07,the detection limit was 3.3 nmol/L.4.Detection of BPA based on CNT@mC/Au-Apt modified electrode:The nano-metal doped into CNT@mC could improve the conductivity of materials and electrochemical catalytic ability,reduce overpotential,increase peak current.Based on the CNT@mC sponge substrate,the gold nanoparticles?Au NPs?were reduced to CNT@mC/Au by constant potential deposition method,and the GCE/CNT@mC/Au was prepared by CNT@mC/Au.Than,aptamer was modified onto GCE/CNT@mC/Au to prepare GCE/CNT@mC/Au-Apt.GCE/CNT@mC/Au-Apt GCE/Au-Apt?GCE/CNT/Au-Apt?GCE/G/Au-Apt were analyzed by CV?EIS?DPV and i-t.Compared with GCE/Au-Apt?GCE/CNT/Au-Apt and GCE/G/Au-Apt,the response of GCE/CNT@mC/Au-Apt to BPA was the most sensitive,with detection limit as low as 0.33 nmol/L and linear range of 0⁷nmol/L.Compared with the method in?3?,the detection of BPA,GCE/CNT@mC/Au-Apt is more advantageous in terms of sensitivity.