Scientists at the Institute of Nano Science and Technology (INST) in Mohali have made significant advances in understanding proton adsorption on catalyst surfaces, which could lead to more efficient production of green hydrogen.
Key Scientific Discoveries
- A new heterostructure combining Copper Tungsten Oxide (CuWO₄) and Copper Oxide (CuO) has been developed, leveraging the Built-In Electric Field (BIEF) effect to improve hydrogen production.
- The structure is formed by growing CuWO₄ nanoparticles on a Cu(OH)₂ precursor, resulting in a p-n heterojunction that creates an asymmetric electronic environment.
- The BIEF plays a pivotal role in controlling proton adsorption and desorption, which directly affects the efficiency of the Hydrogen Evolution Reaction (HER).
Proton Adsorption Mechanism
- The interface between CuO and CuWO₄ reveals variations in Gibbs Free Energy (∆G), particularly near the depletion region.
- The ∆G gradient across this interface enhances hydrogen adsorption at CuO and desorption at CuWO₄, optimizing the system for HER.
- This demonstrates a phenomenon known as “negative cooperativity,” where stronger proton binding at one site decreases the binding at other sites, facilitating proton desorption—an essential step for hydrogen production in alkaline conditions.
What is Green Hydrogen?
- Green hydrogen is generated by the electrolysis of water using renewable energy sources such as solar, wind, or hydropower, emitting no greenhouse gases.
- It is a clean, sustainable, and versatile energy carrier, with water vapour as its only by-product.
- Unlike grey hydrogen (produced from fossil fuels), green hydrogen helps eliminate carbon emissions.
Methods of Green Hydrogen Production
- Alkaline Electrolysis: A well-established and cost-effective method using KOH/NaOH electrolytes and nickel/platinum electrodes.
- Proton Exchange Membrane (PEM) Electrolysis: A highly efficient and fast process, but expensive due to the use of precious metal catalysts.
- Solid Oxide Electrolysis (SOEC): Operates at 700–1000°C, enabling co-electrolysis of H₂O and CO₂, but involves complex materials and high costs.