Indian scientists produce green hydrogen by splitting water molecules

Green hydrogen is one of the cleanest fuels known, capable of decarbonising industries, powering vehicles, and storing renewable energy. Yet, until now, scalable and affordable production methods remained elusive.

The CeNS team developed green hydrogen using only solar energy and earth-abundant materials, without relying on fossil fuels or expensive resources.

“By selecting smart materials and combining them into a heterostructure, we have created a device that not only boosts performance but can also be produced on a large scale,” said Dr. Ashutosh K. Singh from CeNS, who led the research.

“This brings us one step closer to affordable, large-scale solar-to-hydrogen energy systems,” he added.

In the research, published in the Journal of Materials Chemistry A, the team designed a state-of-the-art silicon-based photoanode using an innovative n-i-p heterojunction architecture, consisting of stacked n-type TiO2, intrinsic (undoped) Si, and p-type NiO semiconductor layers, which work together to enhance charge separation and transport efficiency.

The materials were deposited using magnetron sputtering -- a scalable and industry-ready technique that ensures precision and efficiency. This thoughtful engineering approach allowed better light absorption, faster charge transport, and reduced recombination loss, key ingredients for efficient solar-to-hydrogen conversion.

This is more than just a lab success. The device achieved an excellent surface photovoltage of 600 mV and a low onset potential of around 0.11 VRHE, making it highly effective at generating hydrogen under solar energy.

Even more impressively, it showcased exceptional long-term stability, operating continuously for over 10 hours in alkaline conditions with only a 4 per cent performance drop, a rare feat in Si-based photoelectrochemical systems.

This new device is attractive for several reasons, including high efficiency, low energy input, robust durability, and cost-effective materials, all in one package, the researchers said.

It even demonstrated successful performance at a large scale, with a 25 cm2 photoanode delivering excellent solar water-splitting results.

With further development, the technology could fuel hydrogen-based energy systems, from homes to factories, all powered by the sun, the team said.