By Georgina Johnson
Dr Avner Rothschild is working on new, efficient ways of using sunlight to split water into hydrogen and oxygen. Hydrogen is a clean and potentially abundant alternative to fossil fuels. Its large-scale use could lead to the sustainable development, energy independence, and security of many nations.
One of many powerful scientists tackling basic and applied problems in energy science and technology, Dr Avner Rothschild, of the Grand Technion Energy Program (GTEP) and the Faculty of Materials Engineering, has a penchant for high targets. Not only has his life-time hobby been climbing impossible cliff-faces, he also has a powerful vocation to make solar-produced hydrogen a viable future energy alternative.
Rothschild’s group in Technion’s Electroceramics Materials and Devices Laboratory is part of a large European collaborative project looking to split water into hydrogen and oxygen using the energy of the sun - thus creating a 100 percent clean fuel. “We try to produce hydrogen and oxygen by splitting water. The process is possible - it works - but the problem is low efficiency.”
His team is developing nanostructured metal-oxides for applications in environmental and energy conversion technologies. The group has a strong expertise in investigating electronic and ionic defects in semiconducting and mixed ionic-electronic conducting oxides and their effect on transport properties and electrochemical processes.
The scientific barrier is efficiency, says Rothschild, who sees the promise in the development of new electroceramic materials. “We are engineering tandem cells - several different cells, each one with a different aspect of energy from the sun. We are aiming at 5,000 hours stable operation at 10 percent efficiency.”
“We started this project at 3 percent efficiency,” says Rothschild. “Now we are at 5 percent. Our goal is still more - 10 percent - but it is within reach.”
NanoPEC (Nanostructured Photoelectrodes for Energy Conversion) is the European consortium at work with Dr Avner Rothschild to crack the codes of clean hydrogen production and complement Rothschild’s studies in new materials with research from basic science to integration of total systems. The consortium, including groups from Italy, Netherlands, Norway, Poland, Portugal, and Switzerland which meet four times a year, is under the scientific leadership of Prof. Michael Grätzel, director of the Laboratory of Photonics and Interfaces (LPI) of the Swiss Federal Institute of Technology of Lausanne. In 2007, Grätzel received Technion’s prestigious Harvey Prize in science and technology and recently, in June 2010, the Finnish Millennium Technology Prize - the largest technology prize in the world - for development of dye-sensitized solar cells.
Photoelectrochemical cells (PECs) can split water directly into H2 and O2 via photoelectrolysis, and in so doing provide a basis for a renewable, clean production of hydrogen from sunlight. They rely on a photoactive material - a semiconductor - capable of harvesting and converting solar energy into stored chemical fuel, namely, hydrogen. Very little hydrogen gas is present in Earth’s atmosphere, but hydrogen is locked up in enormous quantities in water, hydrocarbons (such as methane), and other organic matter. Efficiently producing hydrogen from these compounds is one of the challenges of using hydrogen as a fuel.