Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nanotechnology points the way to greener pastures

28.03.2011
Nourishing crops with synthetic ammonia (NH3) fertilizers has increasingly pushed agricultural yields higher, but such productivity comes at a price. Over-application of this chemical can build up nitrate ion (NO3–) concentrations in the soil—a potential groundwater poison and food source for harmful algal blooms. Furthermore, industrial manufacturing of ammonia is an energy-intensive process that contributes significantly to atmospheric greenhouse gases.

A research team led by Miho Yamauchi and Masaki Takata from the RIKEN SPring-8 Center in Harima has now discovered an almost ideal way to detoxify the effects of ammonia fertilizers[1]. By synthesizing photoactive bimetallic nanocatalysts that generate hydrogen gas from water using solar energy, the team can catalytically convert NO3– back into NH3 through an efficient route free from carbon dioxide emissions.

Replacing the oxygen atoms of NO3– with hydrogen is a difficult chemical trick, but chemists can achieve this feat by using nanoparticles of copper–palladium (CuPd) alloys to immobilize nitrates at their surfaces and catalyzing a reduction reaction with dissolved hydrogen atoms. However, the atomic distribution at the ‘nanoalloy’ surface affects the outcome of this procedure: regions with large domains of Pd atoms tend to create nitrogen gas, while well-mixed alloys preferentially produce ammonia.

According to Yamauchi, the challenge in synthesizing homogenously mixed CuPd alloys is getting the timing right—the two metal ions transform into atomic states at different rates, causing phase separation. Yamauchi and her team used the powerful x-rays of the SPring-8 Center’s synchrotron to characterize the atomic structure of CuPd synthesized with harsh or mild reagents. Their experiments revealed that a relatively strong reducing reagent called sodium borohydride gave alloys with near-perfect mixing down to nanoscale dimensions.

Most ammonia syntheses use hydrogen gas produced from fossil fuels, but the use of solar energy by the researchers avoids this. They found that depositing the nanoalloy onto photosensitive titanium dioxide (TiO2) yielded a material able to convert ultraviolet radiation into energetic electrons; in turn, these electrons stimulated hydrogen gas generation from a simple water/methanol solution (Fig. 1). When they added nitrate ions to this mixture, the CuPd/TiO2 catalyst converted nearly 80% into ammonia—a remarkable chemical selectivity that the researchers attribute to high concentrations of reactive hydrogen photocatalytically produced near the CuPd surface.

Yamauchi is confident that this approach can help reduce the ecological impact of many classical chemical hydrogenation reactions. “Considering the environmental problems we face, we have to switch from chemical synthesis using fossil-based hydrogen to other clean processes,” she says.

The corresponding author for this highlight is based at the Structural Materials Science Laboratory, RIKEN SPring-8 Center

Journal information
[1] Yamauchi, M., Abe, R., Tsukuda, T., Kato. K. & Takata, M. Highly selective ammonia synthesis from nitrate with photocatalytically generated hydrogen on CuPd/TiO2. Journal of the American Chemical Society 133, 1150–1152 (2011).

gro-pr | Research asia research news
Further information:
http://www.rikenresearch.riken.jp/eng/research/6545
http://www.researchsea.com

More articles from Life Sciences:

nachricht Cells communicate in a dynamic code
19.02.2018 | California Institute of Technology

nachricht Studying mitosis' structure to understand the inside of cancer cells
19.02.2018 | Biophysical Society

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: In best circles: First integrated circuit from self-assembled polymer

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...

Im Focus: Demonstration of a single molecule piezoelectric effect

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...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Contacting the molecular world through graphene nanoribbons

19.02.2018 | Materials Sciences

When Proteins Shake Hands

19.02.2018 | Materials Sciences

Cells communicate in a dynamic code

19.02.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>