Green hydrogen is one of the cleanest fuels known, capable of decarbonizing industries, powering vehicles, and storing renewable energy. Yet, until now, scalable and affordable production methods remained elusive.
In a major leap in this direction, scientists from the Centre for Nano and Soft Matter Sciences (CeNS), Bengaluru, an autonomous institute of the Department of Science and Technology (DST), have developed a next-generation device that produces green hydrogen by splitting water molecules using only solar energy and earth-abundant materials, without relying on fossil fuels or expensive resources.
Led by Dr. Ashutosh K. Singh, the research 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% 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. It even demonstrated successful performance at a large scale, with a 25 cm2 photoanode delivering excellent solar water-splitting results.
