Electrochemical Catalysis And Analytical Application Based On Two-Phase Interface

The interface refers to the interface between the phase of matter and the phase.Because the materials around us exist in three states:gas,liquid,and solid,so there are three phases of gas,liquid,and solid.And there are five different types of interfaces between gas-liquid,gas-solid,liquid-liquid,liquid-solid and solid-solid.When one of the two phases constituting the interface is in the gas phase,it is often called a surface.The primary function of the surfactants we usually know is to change the properties of the surface,liquid-liquid interface and liquid-solid interface of the liquid,with the surface properties of the liquid being of the most importance.Liquid/liquid interface?or oil/water interface?chemistry is an important branch of chemistry and materials science and has a wide range of applications in materials synthesis and electrochemical analysis.For example,a two-phase interface-based synthesis method can be used for synthesizing gold nanoparticles,organic semiconductors,heterogeneous heterostructures,and alloy materials using a two-phase interface.In addition,the two-phase interface method can be used to study the electron transfer reaction,ion transfer reaction of non-electroactive substances,and gradually become an important branch of analytical chemistry,especially the direction of electroanalytical chemistry.This thesis mainly utilizes the two-phase interface method,realizes the two-phase synthesis of novel electrochemical catalysts and realizes the simultaneous detect potassium and sodium ions in mouse brain by using two-phase interface electrochemical probe.The details are as follows:?a?Earthworm-like N,S-Doped Carbon Tube-Encapsulated Co9S8 Nanocomposites Derived from Nanoscaled Metal-Organic Frameworks for Highly Efficient Bifunctional Oxygen Catalysis.1)Due to the metal-organic framework material?MOF?different properties inside and outside the channel,we use two-phase synthesis method to make a coordination complex of thiourea and cobalt ions into the pores of UiO-66-NH₂.2)Carbon nanotube-coated Co₉S₈ nanocomposites?Co₉S₈@CT-800?were prepared by pyrolysis under nitrogen atmosphere.3)Co₉S₈@CT-800 has excellent catalytic activity for ORR and OER processes,and its catalytic performance is comparable to commercial Pt/C and RuO₂.4)The DFT calculation further indicates that the highest catalytically active site is located at the Co site on Co₉S₈,and the intermediate process of adsorbing O₂ to form OOH*is the most important step of catalyzing the O₂ reaction.5)The two-phase synthesis method based on MOF pore structure provides a new research idea for the preparation of novel carbon-based nanocomposites.The results show that the novel MOF-based carbon nanomaterials synthesized by this method have excellent oxygen electrochemical catalytic activity,and their catalytic performance is superior to commercial catalytic materials Pt/C and RuO₂.Co₉S₈@CT nanomaterials not only have excellent activity for oxygen catalysis,but also have better methanol tolerance and cycle stability than commercial materials.After 12 hours of cycle test,the activity remains basically unchanged and the stability is very high.This material with both catalytic activity and high stability is the most suitable choice for battery cathode/anode materials.Finally,using the novel nanomaterials synthesized by this method,we have successfully achieved the electrochemical bifunctional catalysis of oxygen.?b?Simultaneous Electrochemical Detection of K⁺and Na⁺in Rat Brain via Ion Transfer across Micropipet-Based Liquid-Liquid Interface.1)The triazacryptand?TAC?molecule has synthesized,which has a lone pair of four oxygen atoms and a ring structure of a certain size.On this basis,TAC can selectively combine potassium ions and sodium ions because of the different properties of potassium and sodium ions.The binding force of TAC to potassium and sodium ions is also different,so the potential of ion migration is also different.Simultaneous detection of potassium and sodium can be achieved according to different migration potentials.2)Construct a liquid-liquid interface electrochemical detection platform.A quartz glass tube with a diameter of about 5?m was prepared by a P-2000 instrument.Insert Pt wire into the glass tube and fill the organic phase and organic phase supporting electrolyte,then connect it to the electrochemical workstation to successfully build a liquid/liquid interface electrochemical detection platform.3)In vivo analysis.Due to the influence of intracranial pressure in the brain of mice,it is difficult to directly implant the liquid-liquid interface probe into the brain of the mice.It is necessary to modify the liquid/liquid interface platform to meet the requirements of in vivo detection.The introduction of an appropriate amount of polyvinyl chloride?PVC?into the organic phase can achieve a slight solidification of the organic phase and eliminate the effects of intracranial pressure.Finally,based on the above analytical performance,the simultaneous detection of potassium and sodium ions in the brain of Alzheimer's disease model mice was successfully achieved.