Study Of The Solid-Liquid Interface Using Ion Beam Analysis

The composition and dynamic changes of elements or ions?charges?at the solid-liquid interface reflect the mechanism of chemical reactions and interactions at the interface,but the in-situ real-time and high-precision measurement is always a technical problem.Ion beam analysis?IBA?,as a highly sensitive method for analyzing the surface properties of materials,can only be carried out in vacuum,and can not directly measure the interface between liquid and solid.In this thesis,the preparation of solid-liquid interface probes for ion beam analysis in vacuum environment and ion beam analysis technology for solid-liquid interface have been studied,which provides a technical solution for high-precision solid-liquid interface element analysis and dynamic study.In this thesis,the probe of solid metal electrode and electrolyte interface was prepared by using silicon nitride-aluminium film of 25 nanometers as vacuum sealing window and electrochemical electrode.The experimental results show that the solid-liquid interface probe with electrolyte solution works successfully in 1.3*10^-5Pa high vacuum environment.The thin analysis window of the interface probe can withstand the irradiation of 2 MeV He⁺ion flux of 1.0*10¹⁸ ions/cm²,and realize the on-line regulation of the solid-liquid interface voltage.Ion beam analysis and microbeam imaging analysis of solid-liquid interface electrode systems with 0.01M BaCl₂ and 1M LaCl₃ solutions were successfully carried out in Fudan University nuclear microprobe using particle-induced X-ray?PIXE?and Rutherford backscattering Spectroscopy?RBS?techniques.PIXE experiments showed that the relative content of La/Cl ratio increased when negative voltage was applied to the solid-liquid interface electrode,and the relative content of La/Cl ratio decreased when positive voltage was applied.RBS experiments showed that electrolyte ions accumulated at high concentration on the surface of 1M LaCl₃solid-liquid interface electrode at negative voltage?-2.3V?,and at positive voltage?+2.3V?,electrolyte ions distributed at low concentration on the surface of the electrode,and the electrolyte solution tended to bulk concentration at about 1250nanometers depth.In order to improve the accuracy of ion beam analysis of solid-liquid interface,the differential RBS method was discussed in this paper,and the differential spectra of solid-liquid interface elements under applied bias were calculated and simulated.The depth resolution of the solid-liquid interface RBS experiment was about 20 nanometers,which is impossible to resolve the possible double layer structure formed at the solid-solution interface.