Graduate
  1. Physical Chemistry  1.1. Thermodynamics  1.1.1. Laws of Thermodynamics  1.1.2. Enthalpy and heat capacity  1.1.3. Entropy and free energy  1.1.4. Phase Equilibrium  1.1.5. Statistical thermodynamics  1.1.6. Thermodynamic cycle  1.1.7. Fugacity and activity  1.2. Quantum Chemistry  1.2.1. Principles of quantum mechanics  1.2.2. Schrödinger Equation  1.2.3. Particle in a box  1.2.4. Operators and eigenvalues  1.2.5. Atomic orbitals  1.2.6. Molecular orbital theory  1.2.7. Perturbation theory  1.2.8. Valence bond theory  1.2.9. Hybridization and chemical bonding  1.3. Chemical kinetics  1.3.1. Rate laws and reaction mechanisms  1.3.2. Collision theory  1.3.3. Transition state theory  1.3.4. Enzyme Kinetics  1.3.5. Chain Reactions and Polymerization  1.3.6. Photochemical reactions  1.4. Statistical mechanics  1.4.1. Partitioning functions  1.4.2. Molecular distribution functions  1.4.3. Boltzmann Distribution  1.4.4. Bose–Einstein and Fermi–Dirac statistics  1.5. Spectroscopy  1.5.1. Rotational Spectroscopy  1.5.2. Vibrational Spectroscopy  1.5.3. Electronic Spectroscopy  1.5.4. Nuclear magnetic resonance spectroscopy  1.5.5. Mass Spectrometry  1.5.6. Raman Spectroscopy  1.5.7. Electron paramagnetic resonance spectroscopy  1.6. Surface and colloidal chemistry  1.6.1. Absorption isotherm  1.6.2. Surface tension and wetting  1.6.3. Colloidal Stability  1.6.4. Catalysis  1.6.5. Emulsions and micelles  1.7. Electrochemistry  1.7.1. Nernst equation  1.7.2. Electrochemical cells  1.7.3. Conductivity and mobility  1.7.4. War  1.7.5. Fuel cells  1.7.6. Electrolysis
  2. Organic chemistry  2.1. Reaction mechanism  2.1.1. Nucleophilic substitution reactions  2.1.2. Electrophilic addition reactions  2.1.3. Elimination reactions  2.1.4. Rearrangement reactions  2.1.5. Radical reactions  2.1.6. Pericyclic reactions  2.2. Spectroscopy and structural determination  2.2.1. UV-Vis Spectroscopy  2.2.2. IR Spectroscopy  2.2.3. NMR Spectroscopy  2.2.4. Mass Spectrometry  2.2.5. X-ray crystallography  2.3. Stereoscopic  2.3.1. Chirality and optical activity  2.3.2. Structural analysis  2.3.3. Geometrical isomerism  2.3.4. Dynamic Stereochemistry  2.4. Organometallic Chemistry  2.4.1. Organolithium and organomagnesium reagents  2.4.2. Palladium-catalyzed cross-coupling reactions  2.4.3. Transition Metal Complexes  2.4.4. Metal–carbon bond  2.5. Polymer chemistry  2.5.1. Polymerization mechanism  2.5.2. Polymer Characteristics  2.5.3. Biodegradable Polymer  2.5.4. Conducting polymer  2.5.5. Supramolecular polymers  2.6. Medicinal chemistry  2.6.1. Drug design and development  2.6.2. Pharmacokinetics and pharmacodynamics  2.6.3. Structure-activity relationships  2.6.4. Molecular docking and drug screening
  3. Inorganic chemistry  3.1. Coordination chemistry  3.1.1. Crystal field theory  3.1.2. Ligand field theory  3.1.3. Spectrochemical Series  3.1.4. Chelation and stability  3.2. Organometallic Chemistry  3.2.1. Metal Carbonyls  3.2.2. Catalysis by organometallic complexes  3.2.3. Metallocenes  3.3. Bio-inorganic chemistry  3.3.1. Metalloproteins and enzymes  3.3.2. The role of metals in biological systems  3.3.3. Metal ion transport and storage  3.4. Solid state chemistry  3.4.1. Crystal Structures  3.4.2. Band theory of solids  3.4.3. Superconductors  3.4.4. Defects in the crystal  3.5. Lanthanides and Actinides  3.5.1. Electronic configuration in lanthanides and actinides  3.5.2. Coordination chemistry of the lanthanides  3.5.3. Magnetic Properties of Lanthanides
  4. Analytical chemistry  4.1. Chromatography  4.1.1. Gas Chromatography  4.1.2. High Performance Liquid Chromatography  4.1.3. Thin Layer Chromatography  4.2. Spectroscopic Techniques  4.2.1. Atomic absorption spectroscopy  4.2.2. X-ray diffraction  4.2.3. Inductively coupled plasma spectroscopy  4.3. Electroanalytical methods  4.3.1. Potentiometry  4.3.2. Voltammetry  4.3.3. Colometry  4.4. Mass Spectrometry  4.4.1. Ionization Technique  4.4.2. Fragmentation Pattern  4.5. Chemometrics  4.5.1. Multidisciplinary analysis  4.5.2. Machine Learning in Chemistry
  5. Theoretical and Computational Chemistry  5.1. Molecular dynamics simulation  5.1.1. Force fields and energy minimization  5.1.2. Monte Carlo simulation in molecular dynamics simulations  5.2. Quantum chemical methods  5.2.1. Hartree–Fock theory  5.2.2. Density functional theory  5.2.3. Semi-empirical methods  5.3. Computational drug design  5.3.1. Molecular Docking  5.3.2. QSAR Modeling  5.3.3. Virtual Screening
  6. Biochemistry  6.1. Enzyme Kinetics  6.1.1. Michaelis-Menten kinetics  6.1.2. Inhibition mechanism  6.2. Metabolism and Bioenergetics  6.2.1. Glycolysis  6.2.2. Citric acid cycle  6.2.3. Electron transport chain  6.3. molecular Biology  6.3.1. DNA replication and repair  6.3.2. Protein synthesis  6.3.3. Gene Regulation  6.4. Structural Biochemistry  6.4.1. Protein Folding  6.4.2. Membrane Biophysics
  7. Environmental Chemistry  7.1. Atmospheric Chemistry  7.1.1. Greenhouse gases  7.1.2. Ozone depletion  7.1.3. Air pollutants and smoke  7.2. Water Chemistry  7.2.1. pH and water hardness  7.2.2. Wastewater treatment  7.2.3. Aquatic Chemistry  7.3. Soil Chemistry  7.3.1. Heavy metal contamination  7.3.2. Soil pH and Buffering  7.3.3. Nutrient cycling  7.4. Toxicology and Chemical Safety  7.4.1. Toxicokinetics  7.4.2. Risk Assessment in Toxicology and Chemical Safety in Environmental Chemistry  7.4.3. Effects of pollutants on the environment

Graduate → Physical Chemistry → Electrochemistry ↓


Fuel cells


Fuel cells are electrochemical devices that convert chemical energy from a fuel into electricity through the electrochemical reaction of hydrogen and oxygen. Unlike conventional combustion engines, which burn fuel to produce heat that drives a mechanical process, fuel cells generate electricity directly through the movement of electrons.

Basic principles of fuel cells

Fuel cells work like batteries, but they do not run out or need to be recharged. As long as there is a constant supply of fuel and oxidant, a fuel cell can produce electricity. The main components of a fuel cell are the anode, cathode, and electrolyte. Fuel cells also require a fuel, usually hydrogen, and an oxidant, usually oxygen.

Electrochemical reactions in fuel cells

Hydrogen gas is introduced at the anode and is oxidized into protons and electrons:

2H₂ → 4H⁺ + 4e⁻

The electrons pass through an external circuit, producing electricity. At the same time, oxygen gas at the cathode combines with these electrons and protons to form water:

O₂ + 4H⁺ + 4e⁻ → 2H₂O

Overall chemical equation

In a hydrogen fuel cell, water is produced by combining oxygen and hydrogen in the overall reaction:

2H₂ + O₂ → 2H₂O

The structure of fuel cells

The main components and their functions are as follows:

  • Anode: Where the fuel (hydrogen) is oxidized and electrons are released.
  • Cathode: Where oxygen is reduced, and electrons and protons combine to form water.
  • Electrolyte: Conducts ions, but not electrons, between the anode and cathode, and internally completes the circuit.

Types of fuel cells

Fuel cells are classified based on the type of electrolyte used in them, which determines their applications and operating temperatures.

Proton exchange membrane (PEM) fuel cells

These cells operate at relatively low temperatures and have very high power densities, making them suitable for vehicles and portable devices. PEM fuel cells use a solid polymer membrane as the electrolyte.

Solid oxide fuel cells (SOFCs)

They operate at very high temperatures (800°C to 1000°C), allowing them to use a variety of fuels. Their efficiency is very high and they can produce electricity and heat simultaneously.

Alkaline fuel cell (AFC)

These were one of the first types developed and were used in the Apollo space missions. They use an alkaline electrolyte such as potassium hydroxide solution.

Phosphoric acid fuel cells (PAFCs)

These are medium temperature fuel cells that use liquid phosphoric acid as the electrolyte. They are used for stationary power generation.

Applications of fuel cells

Fuel cells can be used in a variety of applications, including:

  • Transportation: Cars, buses and even forklifts can be powered by fuel cells.
  • Stationary power generation: Fuel cells can provide primary or backup power for buildings and industrial facilities.
  • Portable power: Fuel cells can power portable electronics and serve as chargers.

Advantages of fuel cells

Fuel cells offer several advantages over conventional energy sources:

  • High efficiency: Fuel cells can convert a high proportion of the chemical energy in fuel directly into electricity.
  • Environmental friendliness: They have low emissions and when using hydrogen, the only byproduct is water.
  • Scalability: Fuel cells can be used in small hand-held devices or large-scale power plants.
  • Quiet operation: Unlike combustion engines, fuel cells operate quietly.

Challenges of fuel cells

Despite their advantages, fuel cells face challenges:

  • Cost: The cost of materials, especially the catalyst, can make fuel cells expensive.
  • Durability: For example, PEM fuel cells can degrade at high operating temperatures and pressures.
  • Fuel supply: Establishing a comprehensive hydrogen fueling infrastructure is challenging.

The future of fuel cells

The future of fuel cells is promising, especially with ongoing research to overcome existing challenges. Advances in materials science aim to reduce the cost of fuel cells and improve their efficiency and durability. Similarly, efforts are underway to develop an efficient hydrogen supply infrastructure.

Conclusion

Fuel cells represent an important technological advancement in electrochemistry. By providing a cleaner, more efficient way to generate electricity, they offer a path to reducing dependence on fossil fuels and minimizing environmental impact. As research and technology continue to develop, fuel cells could become a more prominent part of the global energy landscape.

Visual example of fuel cell function

Anode Cathode Electrolyte H₊ and e⁻ flow Water and heat

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Fuel cells

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