Researchers at the University of Birmingham have developed a low-temperature thermochemical water-splitting process that could reduce the cost of hydrogen production and allow hydrogen to be generated using waste heat from industrial sites.
The research, published in the International Journal of Hydrogen Energy, demonstrates the use of a perovskite catalyst capable of producing hydrogen at temperatures between 150°C and 500°C. Existing thermochemical water-splitting catalysts typically require temperatures of 700°C to 1000°C during hydrogen production and up to 1500°C for regeneration.
The Birmingham team, led by Professor Yulong Ding from the School of Chemical Engineering, found that the new catalyst can be regenerated at temperatures between 700°C and 1000°C, reducing overall process temperatures by around 500°C.
Hydrogen is widely viewed as an important low-carbon energy carrier because it produces only water and heat at the point of use. It can also be used in fuel cells to generate electricity. Despite this, around 95% of hydrogen production currently relies on fossil fuels.
Thermochemical water splitting is attracting growing interest as an alternative production pathway because it separates water into hydrogen and oxygen using heat and catalysts rather than electricity. Lowering the operating temperature could make the process more practical for industrial deployment and reduce energy requirements.
Professor Ding said: “The lower overall temperature of the process could enable hydrogen to be produced nearby renewable energy generation plants, and foundation industry sectors such as steel, cement, glass and chemicals have an abundance of waste heat, which could be harnessed as the heat input for low-temperature hydrogen production. If the hydrogen is used locally, this would overcome the obstacles presented by storage and transport, so enabling the uptake of hydrogen fuel without the need for costly infrastructure.”
The study focused on perovskites made from barium, niobium, calcium and iron, known as BNCF perovskites. Perovskites are lattice-structured materials capable of absorbing oxygen into their structure and splitting oxygen-containing molecules into constituent parts.
Researchers identified a formulation called BNCF100 as the optimum catalyst. Testing showed it retained hydrogen production performance over 10 operational cycles with little structural degradation observed through X-ray diffraction analysis.
The materials used in the catalyst are readily available and do not require complex synthesis processes or toxic components. According to the researchers, the findings suggest BNCF perovskites absorb oxygen at substantially lower temperatures than previously understood.
A provisional techno-economic analysis conducted as part of the research suggested the process could produce hydrogen at lower cost than both green hydrogen produced by electrolysis and blue hydrogen produced from methane combined with carbon capture and storage. The strongest cost advantage was identified in regions with low renewable energy prices, including Australia.
Hydrogen production remains heavily dependent on steam methane reforming, which currently accounts for almost half of global hydrogen supply. While established and comparatively low cost, the process generates carbon dioxide emissions unless paired with carbon capture systems.
Electrolysis is viewed as a cleaner production route because it uses electricity to split water into hydrogen and oxygen. However, its higher production costs and reliance on large supplies of renewable electricity have limited deployment to around 4% of global hydrogen production.
Other emerging approaches, including photonic water-splitting methods driven by light, are still in early stages of development and face challenges related to efficiency and commercial scale-up.
The Birmingham research was conducted in collaboration with the University of Science and Technology Beijing (USTB). The technology is now being commercialised in the UK and Europe through University of Birmingham Enterprise, which has filed a patent application covering the use of BNCF catalysts for low-temperature water splitting.
The university is currently seeking development partners to support further advancement of the technology and potential commercial deployment.
Professor Ding said: “Our research revealed a catalyst capable of produced substantial yields of hydrogen at relatively low temperatures, and a preliminary techno-economic study shows it is cost-effective compared to the established blue and green pathways for hydrogen production.”
