SU1317351A1 - Method and apparatus for controlling the curreng of pulsed-potentiostatic unit - Google Patents

Abstract

The invention relates to the field of potentiostatic analysis and electrolysis and can be used for a wide class of electrochemistry and pure metallurgy tasks. The aim of the invention is to improve the performance of electrolysis by optimizing the current-free pauses during impulse operation during process automation. The method implements an adaptive procedure for changing the operating mode of a three-electrode electrochemical cell connected to a pulse potentiostat, and adjusts the duty cycle of the pulses of the supply cell. The control information signal is the derivative of the voltage between the working electrode and the reference electrode. When the derivative reaches a certain pre-selected pause value, the next operating current pulse automatically ends and is supplied by the current pulse shaper controlled by a signal from the threshold device, where the signals from the differentiating amplifier and the reference voltage source are compared. 2 Il. (L with SD

Description

113

The invention relates to means and methods for potentiostatic analysis and electrolysis using a pulsating electrolysis current.

The purpose of the invention is to increase the production of electrolysis by optimizing the duration of dead time and automating measurements,

Figure 1 shows a block diagram of a device for carrying out the proposed method; FIG. 2 shows time diagrams of operation of various parts of the circuit as a function of time (t).

A device for implementing the proposed method comprises a pulse potentiostat 1, a three-electrode electrochemical cell 2, a driver of 3 current pulses of an electrochemical cell, a differentiating amplifier 4, a threshold element 5, a source 6 of the reference stabilized voltage. Auxiliary electrode 7 cells 2 through the pulse shaper 3 is connected to the first input of potentiostat 1, the working electrode 8 of cell 2 and comparative electrode 9 of cell 2 are connected to the second and third outputs, respectively. Two-wire is connected to the second and third outputs of potentiostat 1, respectively input of differentiating amplifier 4, the output of which and the output of source 6 are connected respectively to the first and second inputs of the threshold element 5, the output of the threshold element is connected to the control input ohm shaper 3, which is made according to the scheme of a multivibrator with external control.

A method for controlling the current of a pulse-potentiostatic installation consists in passing a pulsed current with a constant frequency and a controlled duty cycle through the three-electrode electrochemical cell, measuring the stationary potential of the working electrode relative to the electrodes, and comparing the time interval of the pause is measured by the dynamic potential of the working electrode relative to the reference electrode, which determine the rate of decline in the potential after the prodosddeni The extremum is recorded as the instant of time when the magnitude of the speed reaches in advance for

73512

of this value, and at this moment in time, the next current effect

The method is carried out as follows.

Through a three-electrode electrochemical cell 2 a pulsed current is passed with a constant frequency and an adjustable duty cycle selected depending on the magnitude of the stationary potential between the electrodes 8 and 9 (FIG. 2a shows current (I) pulses with time t flowing through the electrochemical cell circuit),

Between the electrodes 8 and 9, the dynamic value of the potential is measured (, the dependence of which over time T is shown in FIG. 26.

 The differentiated voltage value has the form shown in FIG. 2c. The mode of threshold element 5 and source b is chosen so that the device does not respond to the first negative extremum Uj occurring in the initial stage of the workflow.

At the end of the current pulse T, Uj reaches an extremum and begins to decrease.

As soon as Uj reaches

0

0

op

pause ends (dot Cj

five

and

on the time axis),

Thus, the pause has the minimum possible value, due to which the potential utilization efficiency increases in the operating mode and the electrolysis productivity increases. The process is carried out automatically at the expense of additionally inserted into the device blocks 4-6.

Claims (1)

Formula 1, A method for controlling the current of a pulse-potentiostatic installation, which means that a pulsed current with a constant frequency and a controlled duty cycle is passed through the three-electrode electrochemical cell, the working potential of the working electrode relative to the reference electrode is measured, and the working value is determined from the measurement results duty ratio, characterized in that, in order to improve the performance of electrolysis by optimizing the duration3 13 current-free pauses, in the time interval of the pause, the dynamic potential of the working electrode relative to the reference electrode is measured, the potential drop rate is determined, and after passing the extremum, the instant of achievement of a predetermined value is recorded and at this instant of time the next current occurs Vie | 2, A device for current control of a pulse-potentiostatic installation, containing a pulse potentiostat with a three-electrode electrochemical cell, the auxiliary electrode of which is connected to the first output through a pulse shaper. 73514 potentiostat, a working electrode and a comparison electrode are connected to the second and third outputs, respectively, characterized in that, 5 with the aim of automating the measurements, in device introduced differentiating. the amplifier, the reference voltage source and the threshold element, and the current pulse driver are made according to the external control multivibrator circuit, the control input of which is connected to the output of the threshold element, the inputs of which are connected respectively to the outputs of the reference voltage source and differentiation amplifier, the two-wire input of which is connected to the working and reference electrodes. 0 five FI.1 3 Ljv .g Editor A.Revin Compiled by Yu, Korshunov Tehred A. Kravchuk Order 2416/39 Circulation 776 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4 Corrector G, Reshetnik