Solar-powered photocatalytic production of hydrogen
Hydrogen, an alternative clean-burning fuel, is of particular interest to industry and governments given the chronic problems associated with the use of fossil fuels. Whilst huge reservoirs of hydrogen are locked up in water, its extraction requires photocatalytic splitting of water that, even when catalysed by doped catalysts such as nitrogen-doped titanium dioxide, is both costly and inefficient.
To surmount this issue and bring water photolysis onto an industrial scale, Oxford researchers have discovered that irradiation of a nitrogen-doped titanium oxide photocatalyst with visible light at elevated temperatures and pressure compared to conventional methods significantly improves the rate and efficiency of hydrogen evolution. This invention has significant implications for the development of many other green technologies and is not limited to the valuable generation of hydrogen fuel.
Background
As the pressures of climate change continue to grow, the reliance upon renewable energy sources that do not come from fossil fuels or generate CO2 becomes increasingly important. Hydrogen is one source, when burned with oxygen that yields significant amounts of energy and water as a by-product. However, molecular hydrogen is very scarce and must be obtained from other sources.
A huge amount of hydrogen is contained in water, although its extraction from water is non-trivial; photocatalytic splitting of water to yield hydrogen (and oxygen) has not yet proven efficient enough for large-scale hydrogen production and efforts have been focused on the development of photocatalyst with dopants and or co-catalysts.
The invention
Oxford researchers have discovered and developed a novel method to increase both rate and efficiencies in the production of hydrogen from photocatalytic splitting of water.
The methodology consists of irradiating a doped titanium-based photocatalyst with visible light specifically at certain temperatures and pressures, thus leading to:
- Rates that are >50x higher that of conventional methods
- Effiencies >70%
This discovery opens up the technology to industrial application with many other potential uses e.g. the recycling of CO2 to methanol and green ammonia synthesis.
Commercialisation
Oxford University Innovation is currently seeking to license this technology for purposes of development and commercialisation. The method is the subject of a priority patent application.
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