New York, Feb 22: A novel technology holds promise for producing cheap hydrogen fuel that can power cars, trucks and trains.
The trouble with solar fuel production so far is the cost of producing the sun-capturing semiconductors and the catalysts to generate fuel.
The most efficient materials are far too expensive to produce fuel at a price that can compete with gasoline.
In this new method, researchers combined cheap, oxide-based materials to split water into hydrogen and oxygen gases using solar energy with a solar-to-hydrogen conversion efficiency of 1.7 percent – the highest reported for any oxide-based photoelectrode system.
“In order to make commercially viable devices for solar fuel production, the material and the processing costs should be reduced significantly while achieving a high solar-to-fuel conversion efficiency,” explained Kyoung-Shin Choi, a chemistry professor at the University of Wisconsin-Madison.
Choi created solar cells from an inorganic compound called bismuth vanadate using electro-deposition – the same process employed to make gold-plated jewellery or surface-coat car bodies – to boost the compound’s surface area to a remarkable 32 square metres for each gram.
“Without fancy equipment, high temperature or high pressure, we made a nanoporous semiconductor of very tiny particles that have a high surface area,” added Choi.
More surface area means more contact area with water, and, therefore, more efficient water splitting.
“Since no one catalyst can make a good interface with both the semiconductor and the water that is our reactant, we choose to split that work into two parts,” noted Choi.
The iron oxide makes a good junction with bismuth vanadate and the nickel oxide makes a good catalytic interface with water. So we use them together, he added.
This resulted in the construction of an inexpensive all oxide-based photoelectrode system with a record high efficiency, claimed the study published in the journal Science.