What is scan rate in cyclic voltammetry?

In cyclic voltammetry (CV), the electrode potential ramps linearly versus time in cyclical phases (Figure 2). The rate of voltage change over time during each of these phases is known as the experiment’s scan rate (V/s).

What is voltage scan rate?

The voltage scan rate (v) is calculated from the slope of the line. Clearly by changing the time taken to sweep the range we alter the scan rate. The characteristics of the linear sweep voltammogram recorded depend on a number of factors including: The rate of the electron transfer reaction(s)

Why does increasing scan rate increase peak current?

At higher scan rates the rate of diffusion is more than the rate of reaction. Hence, more electrolytic ions reach the electrode electrolyte interface whereas very few ions participate in the charge transfer reaction. Therefore, the current at higher scan rate increase.

What is EPC in cyclic voltammetry?

The corresponding peak potential occurs at (c), and is called the cathodic peak potential (Epc). The Epc is reached when all of the substrate at the surface of the electrode has been reduced. After the switching potential has been reached (d), the potential scans positively from (d) to (g).

How do I choose a scan rate?

The choice of scan rates depends upon the information sought:

1. If the aim is to look for anodic and cathodic reversible peaks, scan rate of about 5 mV per sec is suitable.
2. If the aim is to obtain approximate kinetic parameters, scan rate of 100 mV per sec is adequate.

What is peak current in cyclic voltammetry?

the peak current ratio = ipa/ipc = 1 at all scan rates. the peak current function ip/n1/2 (n = scan rate) is independent of n (see equation for peak current)

Why is peak current proportional to square root of scan rate?

The peak current is proportional to square root of scan rate holds for both reversible and irreversible systems. If it is not proportional, then you’re system is probably quasi-reversible. So you can plot to diagnose the behaviour of the system.

What is a scan rate in retail?

This KPI tells you where you are scanning and the more you are scanning the faster and more efficient you are on your point of sale counter. Dissection Sales / Profitability for a Given Period. Now run the report with a year of data. What you will see is a column with %Scan, the higher the better.

Why does capacitance decrease with scan rate?

As the scan rate increases the diffusion of electrolyte ion into electrode internal structure and pore become difficult (diffusion limitation) and ineffective interaction between the electrolyte and electrode materials occurs therefore the specific capacitance is decrease.

What is capacitive current in cyclic voltammetry?

Capacitive current in cyclic voltammetry exhibits theoretically a rectangular current-voltage shape when the capacitance is independent of the potential. In contrast, it shows a trapezoid rotated by a right angle when the capacitance has linear relation with the potential.