In News:

In a significant scientific milestone, Indian researchers have developed a next-generation, scalable solar-driven device for producing green hydrogen—offering a major boost to clean energy innovation and India’s energy transition goals.

Key Highlights:

• Developed By: Centre for Nano and Soft Matter Sciences (CeNS), Bengaluru — an autonomous institute under the Department of Science and Technology (DST).
• Publication: The findings were published in the Journal of Materials Chemistry A (Royal Society of Chemistry).

What Is Green Hydrogen?

Green hydrogen is produced by splitting water molecules using renewable energy sources, especially solar and wind, without any greenhouse gas emissions. It is a clean energy carrier with the potential to decarbonize heavy industries, power vehicles, and store energy.

The Innovation: Solar-Driven Water Splitting Device

• The device uses only solar energy to split water and produce hydrogen.
• It employs a silicon-based photoanode with an n-i-p heterojunction structure:
  • n-type TiO?, intrinsic (undoped) Si, and p-type NiO layers.
  • This structure enhances charge separation and transport efficiency.
• Fabrication via magnetron sputtering, a scalable, industry-compatible process.

Key Performance Metrics

• Surface photovoltage: 600 millivolts (mV)
• Low onset potential: ~0.11 VRHE
• Stability: Operated continuously for over 10 hours in alkaline medium with only ~4% performance degradation.
• Successfully scaled to a 25 cm² photoanode, showing strong solar-to-hydrogen conversion.

Advantages of the Device

Feature                                                                       Benefit

Pure solar operation                              No external power or fossil fuel input

High energy efficiency                         Better light absorption, reduced recombination loss

Material use                                              Low-cost, earth-abundant materials

Durability                                                   Stable under alkaline conditions

Scalability                                                 Demonstrated potential for industrial-scale production

Strategic Significance

• Accelerates India’s National Green Hydrogen Mission and hydrogen-based economy.
• Supports India’s net-zero emission commitments and climate action.
• Offers a cost-effective, clean energy alternative to fossil fuels in:
  • Hard-to-abate sectors like steel and cement
  • Clean transport solutions
  • Renewable energy storage systems

Why is it in the News?

Developing a domestic manufacturing infrastructure for electrolyzers is expected to reduce the cost of green hydrogen and strengthen India's competitive advantage.

What are Electrolysers?

• Electrolysers are devices that produce hydrogen through a chemical process called electrolysis, which splits water molecules into hydrogen and oxygen molecules using electricity.

How do They work?

• These devices consist of a stack of conductive electrodes separated by a membrane, to which a high voltage and current are applied.
• This induces an electric current in the water, causing it to decompose into its constituents: hydrogen and oxygen.
• The generated oxygen is either released into the atmosphere or stored for future use as a medical or industrial gas.
• The hydrogen produced can be stored as a compressed gas liquefied for industrial use or utilised in hydrogen fuel cells, which power various transportation vehicles like trains, ships, and aircraft.

Types of Electrolysers:

• Alkaline Electrolysers: This technology, predominantly used by the fertiliser and chlorine industries, employs thick membranes and nickel-based electrodes.
  • It currently represents a significant portion of global electrolyser capacity.
• Proton Exchange Membrane (PEM) Electrolysers: Operating at high pressure, PEM electrolysers utilise thin perfluorosulfonic acid (PFSA) membranes.
  • Though they require gold and titanium-plated electrodes and catalysts like platinum, iridium, and ruthenium, they produce high-purity hydrogen and are easy to cool, making them a popular choice.
• Solid Oxide Electrolysis Cell (SOEC) Electrolysers: These devices utilise heat to produce hydrogen from steam and are ideal for locations with available heat sources such as nuclear or industrial facilities.
  • Operating at high temperatures ranging from 500 to 850 degrees Celsius.
• Anion Exchange Membrane (AEM) Electrolysers: Operating at significantly lower temperatures of 50 to 60 degrees Celsius, AEM electrolysers combine the less harsh conditions of alkaline electrolysers with the simplicity and high efficiency of PEM electrolysers.

Electrolyzers and Green Hydrogen Production:

• Green hydrogen is renewable hydrogen produced using water electrolysis technology and electricity generated from renewable energy sources, such as solar or wind.
• It is gaining unprecedented momentum globally, and it is believed that it is a key component in accelerating the shift to clean energy.
• The commercialization of electrolyzers can make green hydrogen more readily available and enable energy systems across the globe to undergo fundamental transformations to lower emissions and reduce their negative impact on the environment.