CELL DESIGN FOR IN-SITU X-RAY-SCATTERING STUDIES OF METAL SOLUTION INTERFACES UNDER ELECTROCHEMICAL CONTROL

During the last decade, there has been an increasing use of synchrotron x-ray techniques for the in situ investigation of the structure and composition of metal/solution interfaces under electrochemical control. While a number of experimental cell designs have been utilized in the past, every one of them has exhibited some shortcomings. This paper describes the development of a wide-angle-accessible, transmission-geometry, sandwich-type, x-ray/electrochemical cell. From an x-ray physics standpoint, this cell allows uninterrupted access over a 180-degrees in-plane angle for all incident and scattering angles between 0-degrees and 75-degrees with respect to the sample surface. It is especially advantageous at small scattering angles because of the uniform and insignificant background scattering. From an electrochemical standpoint, this cell provides a uniform current distribution and continuous, precise potential control of the working-electrode surface; at the same time, it permits easy flushing of the working solution and even accommodates operating with flowing solution. Its only disadvantage is its inability to permit in situ cyclic voltammetry of only one surface of the single crystal.