page_title: Chronoamperometry
section_title: Double Potential Step Chronoamperometry (DPSCA)
hierarchical_section_title: Chronoamperometry / Application / Double Potential Step Chronoamperometry (DPSCA)
caption_attribution_description: English: Cyclic voltammetry cell
context_page_description: Chronoamperometry is an electrochemical technique in which the potential of the working electrode is stepped and the resulting current from faradaic processes occurring at the electrode is monitored as a function of time. The functional relationship between current response and time is measured after applying single or double potential step to the working electrode of the electrochemical system. Limited information about the identity of the electrolyzed species can be obtained from the ratio of the peak oxidation current versus the peak reduction current. However, as with all pulsed techniques, chronoamperometry generates high charging currents, which decay exponentially with time as any RC circuit. The Faradaic current - which is due to electron transfer events and is most often the current component of interest - decays as described in the Cottrell equation. In most electrochemical cells this decay is much slower than the charging decay-cells with no supporting electrolyte are notable exceptions. Most commonly a three electrode system is used.
context_section_description: DPSCA is the technique whose working electrode is applied by the potential stepping forward for a certain period of time and backward for a period of time. The current is monitored and plotted with respect to time. This method starts with an induction period. In this period, several initial conditions will be applied to the electrochemical cell so that cell is able to equilibrate to those conditions. The working electrode potential will be held at the initial potential under these conditions for a specified period (i.e. usually 3 seconds). When the induction period is over, the working cells switch to another potential for a certain amount of time. After the first step is completed, the working electrode's potential will stepped back, usually to the potential prior to the forward step. The whole experiment ends with a relaxation period. Under this period, the default condition involves holding the working electrode potential of initial state for another approximate 1 seconds. When the relaxation period is over, the post experiment idle conditions will be applied to the cell so that the instrument can return to the idle state1. After plotting the current as a function of time, a chronoamperogram will occur  and it can also be used to generate Cottrell plots.
caption: Cell of Cyclic Voltammetry
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