Scientists are using two of the most abundant resources on our planet – water and sunlight – to make hydrogen that can be used to generate power and produce heat.
A joint UK-US team of researchers has determined that an inexpensive semiconductor material can be “tweaked” to generate hydrogen from water using sunlight. The findings could potentially have profound implications for the future of solar energy and alternative fuel.
The research, funded by the U.S. Department of Energy (DOE), was led by Professors Madhu Menon and R. Michael Sheetz at the UK Center for Computational Sciences, and Professor Mahendra Sunkara and graduate student Chandrashekhar Pendyala at the University of Louisiana Conn Center for Renewable Energy Research. Their findings were published this month in the Physical Review Journal
Hydrogen has long been touted as a likely key component in the transition to cleaner energy sources. It can be used in fuel cells to generate electricity, pumped into vehicles to operate internal-combustion engines, and burned to produce heat. When combusted, hydrogen combines with oxygen to form water vapor as its only waste product. Hydrogen also has wide-ranging applications in science and industry.
Because pure hydrogen gas is scarce on Earth, it must be manufactured by unlocking it from other compounds. Thus, hydrogen is not considered an energy source, but rather an “energy carrier.”
Until now, generating hydrogen via water splitting has required large amounts of electricity. As a consequence, to date, most of the hydrogen manufactured has been derived from non-renewable sources, such as coal and natural gas.
Using state-of-the-art theoretical computations, theUK-US team demonstrated that an alloy formed by a 2 percent substitution of antimony (Sb) in gallium nitride (GaN) has the right electrical properties to enable solar light energy to split water molecules into hydrogen and oxygen, a process known as photo-electrochemical (PEC) water splitting. When the alloy is immersed in water and exposed to sunlight, the chemical bond between the hydrogen and oxygen molecules in water is broken. The hydrogen can then be harvested.
“Previous research on PEC has focused on complex materials,” Menon said. “We decided to go against the conventional wisdom and start with some easy-to-produce materials, even if they lacked the right arrangement of electrons to meet PEC criteria. Our goal was to see if a minimal ‘tweaking’ of the electronic arrangement in these materials would accomplish the desired results.”
Gallium nitride is a semiconductor that has been in widespread use to make bright-light LEDs since the 1990s. Antimony is a metalloid element that has been in increased demand in recent years for applications in microelectronics. The GaN-Sb alloy is the first simple, easy-to-produce material to be considered a candidate for PEC water splitting. The alloy functions as a catalyst in the PEC reaction, meaning that it is not consumed and may be reused indefinitely.
Sunkara believes that the GaN-Sb alloy has the potential to convert solar energy into an economical, carbon-free source for hydrogen. “Hydrogen production now produces a large amount of CO2 emissions,” he said. “Once this alloy material is widely available, it could conceivably be used to make zero-emissions fuel for powering homes and cars, [as well as] to heat homes.”
Menon said the research should attract the interest of other scientists across a variety of disciplines. “Photo catalysis is currently one of the hottest topics in science,” he explained. “We expect the present work to have a wide appeal in the community spanning chemistry, physics, and engineering.”
Want to learn more about the latest in communications and technology? Then be sure to attend ITEXPO West 2011, taking place Sept. 13-15, 2011, in Austin, Texas. ITEXPO (News - Alert) offers an educational program to help corporate decision makers select the right IP-based voice, video, fax and unified communications solutions to improve their operations. It's also where service providers learn how to profitably roll out the services their subscribers are clamoring for – and where resellers can learn about new growth opportunities. To register, click here.
Stay in touch with everything happening at ITEXPO… follow us on Twitter
Cheryl Kaften is an accomplished communicator who has written for consumer and corporate audiences. She has worked extensively for MasterCard (News - Alert) Worldwide, Philip Morris USA (Altria), and KPMG, and has consulted for Estee Lauder and the Philadelphia Inquirer Newspapers. To read more of her articles, please visit her columnist page.Edited by
Jennifer Russell
