Technology idea of the week

Olivine: a magnesium iron silicate found in the mantle

Olivine - image from Web Mineral Data

Researchers from University of Lyon have discovered a way to split hydrogen gas from water, using rocks.

Process - information from the original paper Andreani et al, American Journal of Mineralogists, 2013

1. A mixture of olivine minerals and water are heated to around 300 degrees Celsius
2. Small amounts of ruby (aluminium oxide) are added: a source of aluminium atoms
3. Mixture is put into a pressure cooker formed of two diamonds that can increase the pressure to 2000 atmospheres! This is about twice the pressure found at the deepest parts of the ocean. 
4. The olivine removes one oxygen and one hydrogen atom from the water molecules to form the mineral serpentine. This releases a spare hydrogen atom that could be used to generate energy. 

This is the same process that occurs over geological time scales as rocks are buried to form oceans. Serpentine is found in many locations globally. 

Opportunities of this process

• It is a low carbon production of hydrogen which could be used in hydrogen fuel cells (BBC news December 2013)
• The reaction is very quick, much quicker than expected. Breakdown of one crystal in a lab took a number of hours whereas it was expected to take weeks (Andreani et al, American Journal of Mineralogists, 2013)
• Serpentinite absorbs CO2 by carbonation. Therefore this process has two benefits: the production of clean energy and the removal of CO2 from the atmosphere (Physics Online December 2013). 

Finally, as well as the opportunities for a new energy source, this discovery hugely progresses our understanding deep sea process. Life on the sea floor is dominated by organisms that rely on hydrogen and our new understanding of this process helps explain the vast quantities of hydrogen that are available to them. I am interested to see how this research develops over the next few years!