Think carbon dioxide, the greenhouse gas most responsible for far-reaching effects on global climate. Nitrogen is another ubiquitous small-molecule gas that can be transformed into the valuable agricultural fertilizer ammonia.
Plants perform the chemical reduction of atmospheric nitrogen to ammonia as a matter of course, but for humans to do that in an industrial setting, a necessity for modern agriculture, requires subjecting nitrogen to massive amounts of energy under high pressure.
"The current process for reducing nitrogen to ammonia is done under extreme conditions," explains Hamers, a UW-Madison professor of chemistry. "There is an enormous barrier you have to overcome to get your final product."
Breaching that barrier more efficiently and reducing the huge amounts of energy used to convert nitrogen to ammonia — by some estimates 10 percent of the world's electrical output — has been a grail for the agricultural chemical industry. Now, that goal may be on the horizon, thanks to a technique devised by Hamers and his colleagues and published today (June 30, 2013) in the journal Nature Methods.
Like many chemical reactions, reducing nitrogen to ammonia is a product of catalysis, where the catalytic agent used in the traditional energy-intensive reduction process is iron. The iron, combined with high temperature and high pressure, accelerates the reaction rate for converting nitrogen to ammonia by lowering the activation barrier that otherwise keeps nitrogen, one of the most ubiquitous gases on the planet, intact.
"The nitrogen molecule is one of the happiest molecules around," notes Hamers. "It is incredibly stable. It doesn't do anything."
One of the big obstacles, according to Hamers, is that nitrogen binds poorly to catalytic materials like iron.
Hamers and his team, including Di Zhu, Linghong Zhang and Rose E. Ruther, all of UW-Madison, turned to synthetic industrial diamond — a cheap, gritty, versatile material — as a potential new catalyst for the reduction process. Diamond, the Wisconsin team found, can facilitate the reduction of nitrogen to ammonia under ambient temperatures and pressures.
Like all chemical reactions, the reduction of nitrogen to ammonia involves moving electrons from one molecule to another. Using hydrogen-coated diamond illuminated by deep ultraviolet light, the Wisconsin team was able to induce a ready stream of electrons into water, which served as a reactant liquid that reduced nitrogen to ammonia under temperature and pressure conditions far more efficient than those required by traditional industrial methods.
"From a chemist's standpoint, nothing is more efficient than electrons in water," says Hamers, whose work is funded by the National Science Foundation. With the diamond catalyst, "the electrons are unconfined. They flow like lemmings to the sea."
While the method was demonstrated in the context of reducing nitrogen to a valuable agricultural product, the new diamond-centric approach is exciting, Hamers argues, because it can potentially fit a wide range of processes that require catalysis. "This is truly a different way of thinking about inducing reactions that may have more efficiency and applicability. We're doing this with diamond grit. It is infinitely reusable."The technique devised by Hamers and his colleagues, he notes, still has kinks that need to be worked out to make it a viable alternative to traditional methods. The use of deep ultraviolet light, for example, is a limiting factor. Inducing reactions with visible light is a goal that would enhance the promise of the new technique for applications such as antipollution technology.
Robert J. Hamers | EurekAlert!
Newly designed molecule binds nitrogen
23.02.2018 | Julius-Maximilians-Universität Würzburg
Atomic Design by Water
23.02.2018 | Max-Planck-Institut für Eisenforschung GmbH
A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.
In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...
A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.
By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...
Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
23.02.2018 | Physics and Astronomy
23.02.2018 | Health and Medicine
23.02.2018 | Physics and Astronomy