From Gibbs Free Energy Equation to Levich Equation

In tribute to the pioneering work of Josiah Willard Gibbs (1839 - 1903), whose ground-breaking discovery of Gibbs Free Energy has revolutionized the field of thermodynamics and profoundly impacted countless areas of science and engineering. Through his rigorous mathematical formulations and profound insights, Gibbs provided us with a powerful tool to understand and predict the spontaneity and equilibrium of chemical reactions, phase transitions, and complex thermodynamic systems. His legacy continues to inspire generations of scientists and engineers, guiding us toward new frontiers of knowledge and innovation.

In his 1876 groundbreaking work "On the Equilibrium of Heterogeneous Substances," he created the idea of Gibbs Free Energy. Gibbs created a complete theory of thermodynamics in this work. It includes the idea of chemical potential and the rules for determining when a chemical process is in equilibrium.

The Gibbs Free Energy equation is very important for understanding and predicting how chemical processes and phase changes will happen and whether they will be thermodynamically possible.

The Gibbs Free Energy equation is used a lot in chemistry, physics, biology, and materials science, among other science and engineering fields, to study and improve processes that involve moving energy around and changing chemicals. It tells us a lot about the direction and size of chemical processes, phase equilibria, and how stable thermodynamic systems are.

Different Thermodynamic Equations to Determine Free Energy :

There are several equations that can be used to determine Free Energy of any system :

• Gibbs Free Energy Equation
• Gibbs-Helmholtz Equation
• Van 't Hoff Equation
• Nernst Equation
• Clausius-Clapeyron Equation

Importance of Gibbs Free Energy in Particular to Electrochemical Processes :

Finding Gibbs Free Energy is helpful for studying thermodynamics and chemical processes in a number of ways. Here are a few important highlights:

• Predicting Spontaneity: Using Gibbs Free Energy, we can figure out if a chemical reaction will happen on its own given certain circumstances. If the Gibbs Free Energy changes negatively (Δ G < 0 ), it means that a reaction happened on its own. If it changes positively (Δ G > 0 ), it means that the reaction did not happen on its own.
• Checking for Equilibrium: Gibbs Free Energy can help you figure out the conditions that allow a process to reach equilibrium (Δ G = 0). By looking at how Gibbs Free Energy changes as reaction variables like temperature and pressure change, we can figure out what the equilibrium mixture is made of and which way the reaction is going.
• Optimizing Processes: Figuring out how to change the Gibbs Free Energy of chemical events helps us make the best process conditions to get the results we want. We can shift the equilibrium position in a way that is good for the reaction and improve reaction yields by changing things like temperature, pressure, and the concentrations of reactants.
• Stability Analysis: Gibbs Free Energy helps us understand how stable thermodynamic systems are. To make things more stable, systems tend to move toward states with less free energy. We can figure out how stable different stages, solutions, and chemical species are by comparing their Gibbs Free Energy.
• Energy Availability: The Gibbs Free Energy shows how much reversible work a machine can do at its most. We can figure out how much energy is available for useful work like chemical synthesis, motor work, or electrical work by looking at how Gibbs Free Energy changes during a process.

If you know how Gibbs free energy and cell potential are related, you can figure out cell potential from thermodynamic data and thermodynamic data from cell potential. This lets us guess and manage the cell potential in electrochemical processes, which is important for making the best energy converters and building electrochemical devices like batteries, fuel cells, and electrochemical sensors.Getting the best reaction conditions: Finding the Gibbs free energy change (Δ G) of electrochemical processes helps find the best conditions for the reaction to get the most yield, efficiency, and selectivity.

Changing things like temperature, pressure, concentration, and electrode potential can change the Gibbs free energy of electrochemical processes and help them go in the direction that you want them to go. It is important to understand the physics of electrochemical processes in order to make electrochemical systems that work well and last a long time. These systems can be used for many things, like storing energy, stopping corrosion, treating water, and electrocatalysis etc.

Limitations of Gibbs Free Energy in Electrochemical Processes:

Although the Gibbs free energy equation is helpful for studying electrochemical reactions, there are some limitations to keep in mind when using it. These restrictions are emphasized by the following three main points:

• Real-World Electrochemical Systems: The Gibbs free energy equation presupposes idealized conditions, like constant pressure and temperature, which might not necessarily be the case. Problems including temperature fluctuations, uneven concentration gradients, and surface area variations between electrodes are commonplace in real-world electrochemical processes.
• The Gibbs free energy equation ignores kinetic effects like reaction rates, activation energies, and mass transport constraints in favor of thermodynamic ones when modeling electrochemical processes. Kinetic processes, not thermodynamic driving factors, regulate the rate of electrode reactions in a number of electrochemical systems. It is possible to oversimplify electrochemical behavior by ignoring kinetic factors, which in turn can lead to inaccurate predictions of reaction kinetics, reaction processes, and electrode performance under dynamic situations.
• Some electrochemical systems, such as those with complicated reactions, high current densities, or non-equilibrium conditions, may not adhere to the equation's idealized behavior of electrolyte solutions and reversible processes.
• Also, the Gibbs free energy equation might not take into account things like electrode passivation, electrode poisoning, or electrochemical side reactions, which are known to have a big effect on how electrochemical systems behave but are not explicitly included in it.

Some intriguing aspects from Fundamentals to Advanced:

Green hydrogen production is crucial for sustainable and self-sufficient space exploration, especially in microgravity environments like space. It offers a renewable energy source for propulsion, life support systems, and scientific experiments, reducing the need for traditional energy sources in microgravity environments. Green hydrogen can be generated from water using renewable sources like solar power or nuclear energy. It can also be used to utilize local resources, such as water ice on the Moon or Mars, reducing transportation costs and enabling longer-duration missions. Additionally, green hydrogen is environmentally sustainable, generating zero greenhouse gas emissions when produced using renewable energy sources. This transition can help reduce the environmental footprint and contribute to global efforts to mitigate climate change.

Electrochemical processes in space or microgravity environments may exhibit unique behavior due to gravity-induced effects like convection and buoyancy. Specialized equations and models are needed to accurately describe and predict these systems. The Levich equation, commonly used in microgravity environments, describes the mass transfer of electroactive species.