Bright ideas to develop solar fuels

A group of research teams in California, US, has been awarded $122 million (?79 million) to establish a research hub to develop techniques that imitate nature and generate fuel directly from sunlight.

The US Department of Energy (DOE) is financing the Joint Centre for Artificial Photosynthesis (JCAP), with $22 million going towards the project this year and the remainder handed out at a rate of approximately $25 million annually over the following four years. 

The project will be led by the California Institute of Technology (CalTech) in partnership with the DOE’s Lawrence Berkeley National Laboratory, bringing together leading researchers to try to simulate nature’s photosynthetic apparatus for practical energy production.

The aim of the hub is to produce solar fuels - hydrogen or high energy carbon compounds such as methanol and methane - that store energy from the sun in their chemical bonds, rather that producing electricity using photovoltaic systems. In nature, leaves absorb light energy that splits water into hydrogen and oxygen. The hydrogen then converts carbon dioxide into organic molecules, and the hub will try to recreate this in an artificial photosynthetic system.

Nathan Lewis from CalTech will direct the new hub, and explains that research will fall into two categories. The first will accelerate the discovery of light absorbing materials, catalysts that make and break chemical bonds to produce fuels, membranes for use in water oxidations and reductions, and will also build upon existing research techniques.  

’There are starting points that we have identified on each project,’ says Lewis. ’We could start with existing earth abundant hydrogen evolution catalysts like nickel, copper or molybdenum disulfide, or with existing water oxidation catalysts like ruthenium or iridium dioxide and try to improve them,’ he adds. 

The second arm of the project will be devoted to the science that underlies the scale up of the fundamental chemistry so that these solar fuels can be produced industrially, Lewis tells Chemistry World. ’It’s a very exciting project - only a hub could do these activities,’ he says. 

James Barber at Imperial College London, UK - president of the International Society of Photosynthesis Research - welcomes the creation of the hub, explaining that even though we can turn sunlight into electricity at present, the amount of energy we can store using battery technology is nowhere near as much as in the chemical bonds in fuels such as petrol. ’A glass of petroleum contains a lot of energy that cannot be equalled by batteries - you can’t fly a [Boeing] 747 on batteries. That’s the challenge, particularly for transportation: to get high density fuel, in the form of chemical bonds, from sunlight,’ he says. 

However, Barber has concerns that the DOE funding is not proportional. ’Given the scale of the problem, the amount of money allocated although of course useful, is not enough. The leaders of the world tell us that climate change is the biggest issue facing humankind, and I think these are relatively small amounts of money to tackle the problem,’ he states. 

Lewis hopes that the creation of this research hub will inspire other countries to rise to the challenge. ’Our secretary of energy [Steven Chu] has issued a bold challenge to the scientific community to harness their skills and talents and focus them on this energy problem, and try to develop faster, better, cheaper, fundamentally different approaches that will help bridge the gap between where we are now and what is truly needed for a really truly scalable low carbon economy.’ 

Mike Brown