Scientists peel away the mystery behind gold's catalytic prowess

Gold particles measuring less than 5 nanometers in diameter possess a high level of catalytic activity when they are deposited on metal-oxide supports, Haruta learned. One nanometer (nm) is equal to one one-billionth of a meter, or about the width of five atoms.
In particular, Haruta found that gold nanoparticles are effective at catalyzing the critical conversion of toxic carbon monoxide (CO) into more benign carbon dioxide (CO₂) at room temperature and even at temperatures as low as -76 degrees C. CO oxidation is vital to firefighters and others who must enter burning buildings, and it is also critical to the protection of hydrogen fuel cells from CO contamination.

In the two decades since Haruta's discovery, scientists have sought to determine exactly how gold nanoparticles function as catalysts.

Now, researchers from Lehigh University in Bethlehem, Pa., and Cardiff University in the UK believe they have pinpointed the active species at which the critical oxidation reaction occurs when gold is supported on iron oxide.

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Helium Ions Replace Electrons in Novel Microscope Technology

Researchers affiliated with the Institute for NanoBioTechnology hope to gain some insight into the potentially hazardous effects of inhaled nanometals by studying their ability to access lung tissues, their potential to trigger pro-inflammatory reactions by cells that line the lung airways, and even the extent to which workers are exposed in a nanomaterials manufacturing setting.

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Latest global warming report urges world to begin adapting

Global warming is having a measurable effect on Earth's climate, including agriculture, freshwater resources, and plants and animals on both sea and land. These changes are expected to intensify as temperatures continue to rise.

Those are among the conclusions of a new report from the Intergovernmental Panel on Climate Change (IPCC), a UN-sponsored group of scientists. A summary of their findings released April 6 outlines climate changes and how researchers expect them to play out as warming continues. Their impact on society, the IPCC report says, will vary depending on the amount of actual temperature increase that occurs and humanity's capacity or ability to adapt to the changes.

"Not all of these effects are negative," notes Sharon Hayes, an official with the White House Office of Science and Technology Policy, who headed the US delegation to the week-long meeting in Brussels where scientists and political delegations hammered out the summary's final wording. At least during the early part of the century, for example, crop yields in wetter parts of the mid- and high latitudes, including regions of Russia, Canada, and the US, are expected to rise.

But the report also makes clear that as temperatures rise, negative effects increase, Dr. Hayes adds. And the poorest countries, which contribute the least to global warming, are expected to face the biggest challenges in coping with it.

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3-1 JNTU 3-1computer networks by tanenbaum (SOLUTIONS TO PROBLEMS)

click here to download 3-1 JNTU 3-1computer networks by tanenbaum (SOLUTIONS TO PROBLEMS)

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