Overpotential For Anodic Reaction From Tafel Equation Calculator

Tafel Equation:

\[ \eta = +(\text{Tafel Slope}) \times \log_{10}\left(\frac{\text{Electric Current Density}}{\text{Exchange Current Density}}\right) \]

Overpotential (η):

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1. What is the Tafel Equation?

The Tafel equation describes the relationship between the current density through an electrode and the overpotential for electrochemical reactions. It provides fundamental insights into electrode kinetics and reaction mechanisms.

2. How Does the Calculator Work?

The calculator uses the Tafel equation for anodic reactions:

\[ \eta = +(\text{Tafel Slope}) \times \log_{10}\left(\frac{\text{Electric Current Density}}{\text{Exchange Current Density}}\right) \]

Where:

\( \eta \) — Overpotential (Volt)
\( \text{Tafel Slope} \) — Tafel slope constant (Volt)
\( \text{Electric Current Density} \) — Applied current density (A/m²)
\( \text{Exchange Current Density} \) — Exchange current density (A/m²)

Explanation: The equation quantifies the extra potential needed to drive an electrochemical reaction at a specific rate, accounting for the kinetic limitations of the electrode process.

3. Importance of Overpotential Calculation

Details: Overpotential calculation is crucial for understanding electrode performance, optimizing electrochemical processes, designing efficient electrochemical cells, and studying corrosion mechanisms.

4. Using the Calculator

Tips: Enter Tafel slope in volts, current densities in A/m². All values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the physical significance of Tafel slope?
A: The Tafel slope provides information about the reaction mechanism and the rate-determining step in electrochemical processes.

Q2: How is exchange current density determined?
A: Exchange current density is typically determined experimentally by extrapolating the Tafel plot to zero overpotential.

Q3: What factors affect the Tafel slope?
A: Temperature, electrode material, electrolyte composition, and reaction mechanism all influence the Tafel slope value.

Q4: Can this equation be used for cathodic reactions?
A: Yes, but the sign convention changes. For cathodic reactions, the overpotential is typically negative.

Q5: What are typical values for Tafel slope?
A: Tafel slopes typically range from 0.03 to 0.12 V per decade, depending on the electrochemical system and reaction mechanism.