Synthesis And Performance Study Of All-solid State Ion-selective Electrode Materials Based On Pine Cone Biochar Material

As an important analytical detection tool,research on all-solid-state ion-selective electrodes is rapidly developing and is widely used in biomedical,industrial,agricultural and environmental fields due to its advantages of low cost,simple fabrication,miniaturization and real-time detection.Conventional ion-selective electrodes usually choose conductive polymers,graphene,carbon nanotubes and other commercial products as electrode materials,which are prone to instability,slow ion-electron conduction,poor sensitivity and stability in ion detection.Based on this,a material with porous structure,large specific surface area and excellent electrochemical properties was prepared from pine cone biochar in this thesis and used as a solid transconductor layer in an all-solid-state ion-selective electrode,and research work was conducted on the potential drift,potential response and stability of the electrode.The details of the study are as follows:1.Research on calcium ion all-solid ion-selective electrode based on KOH-activated pine cone biochar materialThe initial biochar material was made from pine cone biomass by high temperature carbonization,and then the porous carbon material was activated by different KOH activation ratios.The morphological characterization showed that the carbonized as well as the activated material maintained the original honeycomb structure and showed an excellent pore structure and large specific surface area(1768.072 m²·g^-1)after activation.The electrochemical performance tests show that the material has low electrochemical impedance and electrochemical drift.The experiments show that the all-solid-state ion-selective electrode using this material as a solid transduction layer has good ion-electron transduction ability and stability.2.Research on calcium ion all-solid state ion-selective electrode based on urea nitrogen-doped pine cone biochar materialSince the ion-selective electrode with carbon material as the solid transconductance layer is a bilayer capacitive electrode,the magnitude of its capacitance affects the application range of the ion-selective electrode.Therefore,the doping of nitrogen is achieved by introducing urea in the preparation process,which leads to an increase in specific capacitance and leads to an improvement in the electrochemical properties of the material.Electrochemical experiments show that the prepared material has a large specific capacitance（C=176.4μF）.The all-solid-state ion-selective electrode using this material as a solid transduction layer has excellent stability and potential response.3.Research on calcium ion all-solid state ion-selective electrode based on polypyrrole composite pine cone biochar materialIn the process of detecting ions in solution at ion-selective electrodes,the phenomenon of aqueous layer can occur due to the hydrophobicity of the material,which affects the stability of detection.Therefore,a layer of polypyrrole with hydrophobicity and pseudocapacitance is laminated on the surface of carbon material by chemical oxidation.This enhanced the hydrophobicity of the pine cone biochar material（contact angle changed from 76^°to 105^°）,reducing the possibility of water layer generation and significantly increasing the capacitance of the material.Experiments show that the all-solid-state ion-selective electrode with this material as the solid transduction layer has better stability and electron transfer rate.