The Preparation Of Carbon Based Composites Modified Electrode And Its Application In Detecting Heavy Metals And Catalyzing Methanol Oxidation

Electrochemical method is widely used for detection and catalysis.However,the core component of electrochemical sensor?modified electrode?still has the problems that the modified materials are easy to fall off,and affect the reproducibility.The efficiency and sensitivity of electrochemical detection on heavy metal ions should be improved.Most of the catalysts for methanol oxidation are noble metal catalysts,which are expensive and easily poisoned by the combination of intermediate product CO.To solve the problem that the modified materials are easy to fall off,the modified electrode is prepared by electropolymerization or electrodeposition in this paper.The materials can combines strongly with the electrode,which would has good reproducibility,low temperature and time-saving.In order to improve the efficiency and sensitivity of heavy metal ions detection,carbon materials with high conductivity and polyarginine or polycyclodextrin?rich in amino or hydroxyl groups which are easy to chelate with heavy metal ions?were chooesd and used to detect Pb²⁺and Cd²⁺.In view of the expensive and easily poisoned of noble metal catalysts?methanol fuel cell anode catalysis materials?,electrodeposition is used in this paper to get the materials,which combined carbon materials and nickel aluminum hydrotalcite?nickel based materials can catalyze methanol oxidation efficiently?,it makes sense to look for alternatives to noble metal catalysts.The main contents are as follows:Firstly,carbon nanotubes/poly-L-arginine film materials were obtained by electrochemical polymerization.The structure and morphology of the composite films were characterized by field emission scanning electron microscopy and infrared spectroscopy.The chemical and electrochemical factors such as pH value,pre-enrichment voltage,and pre-enrichment time that affect the detection of heavy metal ions are optimized.Poly-L-arginine can chelate with Pb²⁺.Carbon nanotubes have good conductivity and large surface area,CNTs/poly?L-Arg?materials combine the advantages of both CNTs and poly?L-Arg?,the glassy carbon electrodes modified with CNTs/poly?L-Arg?is superior to the electrodes modified by carbon nanotubes or poly-L-arginine in detecting Pb²⁺,it has a wide linear range,good reproducibility,it also provide a possibility for real applications.Secondly,CNTs/poly??-cyclodextrin?was obtained by electropolymerization.The structure and morphology of the material were characterized by field emission scanning electron microscopy and infrared spectroscopy.Its electrochemical properties were characterized by cyclic voltammetry and electrochemical impedance spectroscopy.The CNTs and poly??-cyclodextrin?form a synergistic effect.After optimization,the CNTs/poly??-CD?is used to simultaneously detect the heavy metal ions Pb²⁺and Cd²⁺.The peak shapes of Pb²⁺and Cd²⁺are clear and do not affect each other.The CNTs/poly??-CD?show great potential in the simultaneous detection of multiple heavy metal ions.Thirdly,a graphene quantum dots/nickel-aluminum hydrotalcite composite film was obtained by one-step electrodeposition method.The electrocatalysis of methanol was studied by cyclic voltammetry and chronoamperometry.Due to the effective recombination of GQD and Ni-Al LDHs,compared with Ni-Al LDHs electrode,the composite electrode exhibits lower oxidation voltage and higher oxidation current when catalyzed on methanol oxidation,it has a wide application prospect.