CATALYTIC GOLD NANOCLUSTERS PROMISE RICH CHEMICAL YIELDS

The reaction mechanism of carbon monoxide oxidation is shown over intact and partially ligand-removed gold nanoclusters supported on cerium oxide rods. Image credit: Wu, Z.; Jiang, D.; Mann, A.; Mullins, D.; Qiao, Z.-A.; Allard, L.; Zeng, C.; Jin, R.; Overbury, S. Thiolate Ligands as a Double-Edged Sword for CO Oxidation on CeO2-Supported Au25(SCH2CH2Ph)18 Nanoclusters. J. Am. Chem. Soc. 2014, 136(16), 6111. (hi-res image)

Courtesy of Oak ridge National Labratory:

Old thinking was that gold, while good for jewelry, was not of much use for chemists because it is relatively nonreactive. That changed a decade ago when scientists hit a rich vein of discoveries revealing that this noble metal, when structured into nanometer-sized particles, can speed up chemical reactions important in mitigating environmental pollutants and producing hard-to-make specialty chemicals. Catalytic gold nanoparticles have since spurred hundreds of scientific journal articles. With the world catalyst market poised to hit $19.5 billion by 2016, gold nanoparticles may find commercial as well as intellectual importance, as they could ultimately lead to novel catalysts for energy, pharmacology and diverse consumer products.

But before gold nanoparticles can be useful to consumers, researchers have to make them both stable and active. Recently, scientists learned to make tiny, highly ordered clusters with very specific numbers of gold atoms that are stabilized by compounds called ligands. These stabilized gold clusters plus ligands may be thought of as large molecules. In collaboration with scientists from Carnegie Mellon University, researchers at the Department of Energy’s Oak Ridge National Laboratory have found one new gold molecule, a catalyst containing exactly 25 gold atoms, that is powerful as well as sophisticated. It catalyzes the conversion of a variety of molecules, including the transformation of poisonous carbon monoxide into harmless carbon dioxide, a reaction that may find application in devices near gas flues or wood-burning stoves. Unfortunately, the ligands that create and stabilize the engineered clusters also block the very sites needed to catalyze the conversion of carbon monoxide into carbon dioxide.

Tiny particles may pose big risk

Courtesy of Anne Trufton @ MIT News:

Thousands of consumer products — including cosmetics, sunscreens, and clothing — contain nanoparticles added by manufacturers to improve texture, kill microbes, or enhance shelf life, among other purposes. However, several studies have shown that some of these engineered nanoparticles can be toxic to cells.

A new study from MIT and the Harvard School of Public Health (HSPH) suggests that certain nanoparticles can also harm DNA. This research was led by Bevin Engelward, a professor of biological engineering at MIT, and associate professor Philip Demokritou, director of HSPH’s Center for Nanotechnology and Nanotoxicology.

The researchers found that zinc oxide nanoparticles, often used in sunscreen to block ultraviolet rays, significantly damage DNA. Nanoscale silver, which has been added to toys, toothpaste, clothing, and other products for its antimicrobial properties, also produces substantial DNA damage, they found.
The findings, published in a recent issue of the journal ACS Nano, relied on a high-speed screening technology to analyze DNA damage. This approach makes it possible to study nanoparticles’ potential hazards at a much faster rate and larger scale than previously possible.

Ball Lightning

Chinese scientists have recorded the rare phenomenon in nature for the first time. Courtesy of Medium.com:

For centuries, people have reported seeing luminous, spherical orbs during storms — a phenomenon known as “ball lightning”. According to eyewitness reports they last for several seconds, moving through the air before eventually exploding.

But meteorologists have always regarded such reports with suspicion, as they’d never been able to observe the phenomenon themselves. Inconsistencies in public reports led those studying these cases starting to think of them like UFO sightings — merely hallucinations, perhaps caused by electromagnetic effects.

Now, however, following years of attempts to replicate ball lightning in the lab, Chinese researchers have finally recorded it in the field.