Aluminium enables cheaper hydrogen production
French scientists have managed to produce hydrogen by accelerating natural processes taking place in rocks deep below the Earth’s surface, possibly opening new avenues for hydrogen production.
The team from the University Claude Bernard in Lyon, France, used aluminium oxide to speed up the process by which hydrogen is naturally produced when water interacts with olivine, a common type of rock, under high temperatures and pressures found deep underground.
Published recently in the journal American Mineralogist, the discovery could pave the way for considerably cheaper hydrogen production. Used in rockets and in battery-like fuel cells, hydrogen is being widely researched as a non-polluting fuel. Fuel cells, which meld hydrogen with oxygen in the air to yield electricity, emit only water, which makes them attractive as a way to cut greenhouse gas emissions and air pollution.The high costs of its production, however, have been hindering its wider deployment.
"We have overcome a preliminary step for a carbon-free energy production," said lead researcher Muriel Andreani.
The addition of aluminium oxide accelerated the natural process by between 7 and 50 times, using temperatures of between 200 and 300 degrees Celsius at a pressure equivalent to twice the depth of the deepest ocean.
In the process, olivine turns into the mineral serpentine and water splits into its components, hydrogen and oxygen.
Currently, the most widely used technology for producing hydrogen - separating it from natural gas - requires far higher temperatures of 700 degrees Celsius and releases heat-trapping carbon dioxide as a by-product.
Using lower temperatures would enable considerable cost reduction. However, to make this process commercially viable, the procedure would have to be scaled-up to allow manufacturing of larger amounts of hydrogen.
"Scaling this up to meet global energy needs in a carbon-free way would probably require 50 years," said Jesse Ausubel of the Rockefeller University in New York. "But a growing market for hydrogen in fuel cells could help pull the process into the market."
The work is part of the Deep Carbon Observatory (DCO), a 10-year project due for completion in 2019 involving 1,000 researchers in 40 nations.