Scanning probe microscopy: SECM (Scanning Electrochemical Microscopy)

Service description

The detection scheme of scanning electrochemical microscopy (SECM) bases on the positioning of a microelectrode (the SECM tip or probe) in close distance towards a sample surface. This miniaturized probe is moved stepwise in a user-defined grid over this sample. The corresponding electrochemical signal at the probe results from the interaction with the surface. A diagram of the tip signal (z-current) versus the position (xy) visualizes the local activity distribution in current values. The probe signal is a faradaic current whose value depends on the particular properties of the surface. The resolution in our SECM depends on the used electrode size, 10 and 25 µm. As opposed to global electrochemical methods, SECM facilitates a locally resolved investigation of reactions rates and complements therefore global methods of analysis in almost all fields of electrochemistry. The scanning electrochemical microscope, includes a high quality steppermotor-controlled xyz-positioning system allowing a 25x25x25 mm scanning range at 20 nm resolution. The electrochemical cell is composed of the Pt-microelectrode or tip (25 or 10 µm), the wotking electrode (sample under study), reference electrode and Pt counterelectrode. A bipotentiostat is used in order to have the possibility to polarize both working electrode and Pt microelectrode (scanning probe). The electrochemical microscope allows the acquisition of current distribution maps from the specific surface, giving rise to an idea about the reactivity of the materials under study. This service will provide localized current distribution maps of the area of interest.