REDOX / Electrochemistry & Electrocatalysis
In general, electrochemistry deals with the study of chemical reactions where electrons are transferred directly between molecules and/or atoms (known as oxidation-reduction or redox reactions). When a substance loses an electron, its oxidation state increases (oxidation) while when it gains an electron, its oxidation state decreases (reduction). A potentiostat is an electronic instrument that enables electrochemical studies using three electrode systems for investigations of reaction mechanisms related to redox chemistry. In almost all applications, the potentiostat measures the current flow between the Working and Counter electrodes. Both electrodes are contained in an electrochemical cell. The controlled variable is the cell potential and the measured variable is the cell current. The potentiostat implements this control by injecting current into the cell through an Auxiliary, or Counter, electrode.
In some advanced applications (i.e. kinetic studies, electrocatalysis), it is required to perform electrochemical measurements under controlled hydrodynamic conditions. In such cases, a low-noise rotating ring disk electrode (RRDE) is commonly used. The ring and disc electrode assembly provides the means to detect reaction intermediates in situthrough collection experiments.
(1) Autolab potentiostat/galvanostat (Model PGSTAT128N) capable of measuring maximum 800 mA, with a compliance voltage of 12 V. Equipped with a dual-mode bipotentiostat module that converts the Autolab potentiostat/galvanostat into a double channel potentiostat (maximum current 50 mA). Potentiostat operates with NOVA electrochemistry software (Metrohm Autolab). Accompanied with a Metrohm Autolab rotating ring disk electrode (RRDE) and rotating disk electrode (RDE) setup (rotation speed 100 – 10,000 rpm). Remote control with NOVA software.
(2) EG&G Princeton Applied Research potentiostat/galvanostat (Model PARTSAT 2273A) connected with a PC running PowerSuite software, capable of measuring maximum current of 2 A, with a compliance voltage of 100 V.
Electroanalytical measurements, Determination of energy levels in organic semiconductors (HOMO-LUMO), Electrocatalysis (oxygen reduction reaction, hydrogen evolution reaction, electro-oxidation of small organic molecules), Reaction kinetics, Sensing / environmental applications
Analytical cell kit (200 ml) fitted with a thermostatic jacket for temperature control, custom-made small volume analytical cell kit (10 ml), reference electrodes (Ag/AgCl, Hg/HgO, Hg/HgSO4), GC disk electrodes, GC disk – Pt ring electrodes, Pt wire counter electrodes.
Dr. Nikos Tagmatarchis, tagmatar@eie.gr
