For clean air

March 30, 2007

In addition to nitrogen oxides and sulfur oxides, many volatile organic compounds (VOCs) in air contribute to smog and high ozone levels, as well as potentially damaging human health. Clean-air laws are thus rightly continuing to become stricter. Most modern air-purification systems are based on photocatalysts, adsorbents such as activated charcoal, or ozonolysis.

However, these classic systems are not particularly good at breaking down organic pollutants at room temperature. Japanese researchers have now developed a new material that very effectively removes VOCs as well as nitrogen- and sulfur oxides from air at room temperature. As they report in the journal Angewandte Chemie, their system involves a highly porous manganese oxide with gold nanoparticles grown into it.

To prove the effectiveness of their new catalyst, the research team headed by Anil K. Sinha at the Toyota Central R&D Labs carried out tests with acetaldehyde, toluene, and hexane. These three major components of organic air pollution play a role indoors as well as out. All three of these pollutants were very effectively removed from air and degraded by the catalyst—significantly better than with conventional catalyst systems.

One secret to the success of this new material is the extremely large inner surface area of the porous manganese oxide, which is higher than all previously known manganese oxide compounds. This large surface area offers the volatile molecules a large number of adsorption sites. Moreover, the adsorbed pollutants are very effectively broken down. There is clearly plenty of oxygen available for oxidation processes within the manganese oxide lattice. Degradation on the surface is highly effective because free radicals are present there. Presumably, oxygen from air dissociates on the gold surface to replace the consumed oxygen atoms in the lattice structure.

This process only works if the material is produced in a very specific manner: The gold must be deposited onto the manganese oxide by means of vacuum-UV laser ablation. In this technique, a gold surface is irradiated with a special laser, which dislodges gold particles through evaporation. These gold particles have unusually high energy, which allows them to drive relatively deep into the surface of the manganese oxide. This process is the only way to induce sufficiently strong interactions between the little clumps of gold and the manganese oxide support.

Citation: Mesostructured Manganese Oxide/Gold Nanoparticle Composites for Extensive Air Purification, Angewandte Chemie International Edition 2007, 46, No. 16, 2891–2894, doi: 10.1002/anie.200605048

ource: John Wiley & Sons

Explore further: Using soft X-ray emission spectroscopy to reveal the behavior of electrons associated with charging and discharging

Related Stories

The finer details of rust

December 4, 2014

Scientists at the Vienna University of Technology have been studying the behavior of iron oxide surfaces. The atomic structure of iron oxide, which had been assumed to be well-established, turned out to be wrong. The behavior ...

The promise and peril of nanotechnology

March 26, 2014

Scientists at Northwestern University have found a way to detect metastatic breast cancer by arranging strands of DNA into spherical shapes and using them to cover a tiny particle of gold, creating a "nano-flare" that lights ...

How your smartphone got so smart

September 16, 2013

In 1947, the Cold War, David Letterman, and the CIA were born; the future Queen Elizabeth got married; and a U.S. postage stamp cost 3 cents. That was also the year the seed that would eventually grow into smartphones first ...

Innovative solutions for urban mining

May 30, 2013

Urban mining is a performed by extracting metal resources from electronic products. Gold from PCBs and Lithium from seawater - read more about Prof. Jai-Koo Park of Hanyang University on his research into urban mining.

Recommended for you

Magnetism at nanoscale

August 3, 2015

As the demand grows for ever smaller, smarter electronics, so does the demand for understanding materials' behavior at ever smaller scales. Physicists at the U.S. Department of Energy's Ames Laboratory are building a unique ...

How the finch changes its tune

August 3, 2015

Like top musicians, songbirds train from a young age to weed out errors and trim variability from their songs, ultimately becoming consistent and reliable performers. But as with human musicians, even the best are not machines. ...

Study calculates the speed of ice formation

August 3, 2015

Researchers at Princeton University have for the first time directly calculated the rate at which water crystallizes into ice in a realistic computer model of water molecules. The simulations, which were carried out on supercomputers, ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.