Electrocatalysis_Presentation_Updated.pptx

hydrogen evolution reaction

1. Electrocatalysis Accelerating Electrochemical Reactions with Electrocatalysts

2. Introduction • Branch of catalysis focused on electrochemical reactions. • Uses electrocatalysts to speed up reactions. • Plays a key role in energy conversion (fuel cells, water splitting, CO₂ reduction).

3. Principle 1 – Activation Energy & Voltage • Every reaction needs activation energy. • In electrochemistry → linked to electrode potential (voltage). • Electrocatalyst lowers activation energy → reduces overpotential. 📊 Figure: Energy barrier diagram (with vs. without catalyst).

4. Principle 2 – Electron Transfer • Core of electrochemical reactions = electron transfer. • Example: Water Splitting - Cathode (reduction): H₂O → H₂ - Anode (oxidation): H₂O → O₂ • Electrocatalyst provides a favorable surface for faster transfer. 📊 Figure: Water-splitting schematic (H₂ at cathode, O₂ at anode).

5. Principle 3 – Surface Reactions • Electrode surface properties determine reaction efficiency. • Strong binding → slow product release. • Weak binding → poor reactant adsorption. • Balanced binding = efficient catalysis. 📊 Figure: Adsorption–desorption cycle illustration.

6. Summary • Electrocatalysts reduce energy demand & increase reaction rates. • Key factors: 1. Lowering activation energy 2. Facilitating electron transfer 3. Optimizing surface interactions • Crucial for green energy technologies. 📊 Figure: Clean energy infographic (H₂, fuel cells, batteries).

7. Basis of Water Splitting • Water splitting = electrochemical reaction where H₂O is split into H₂ and O₂ using electricity or light energy. • Overall Reaction: 2H₂O → 2H₂ + O₂ • Half Reactions: - Cathode (Reduction): 2H₂O + 2e⁻ → H₂ + 2OH⁻ (alkaline) OR 2H⁺ + 2e⁻ → H₂ (acidic) - Anode (Oxidation): 2H₂O → O₂ + 4H⁺ + 4e⁻ • Requirements: - External energy input (electrical or solar). - Efficient electrocatalysts for Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER). 📊 Figure: Diagram of water-splitting cell (H₂ at cathode, O₂ at anode).