New silver catalyst to fight smog in cities

Scientists are creating a new silver catalyst to purify the air that can decompose toxic carbon monoxide and other harmful substances into harmless components, an advance that could help fight smog in cities like New Delhi and Beijing.
This nanostructure catalyst may be effective even at room temperature and could be used as a filter for ventilation.
"Silver catalysts are less studied than other catalysts made with particles of precious metals-gold, platinum, and palladium," said Gregory Mamontov, senior researcher at the Laboratory of Catalytic Research at Tomsk State University in Russia.
"However, they can be just as effective in the oxidation of harmful volatile substances and cheaper by a factor of 10," said Mamontov.

The researchers have synthesised a particular type of silica gel-SBA-15, which consists of 6-10 nanometres diameter nanotubes of silicon oxide, and used it as a basis for preparing the catalyst.
"Each nanotube is used as a nanoscale reactor. Inside, we conduct the synthesis of silver particles and cerium oxide smaller than three nanometres," said Mamontov.

"After that, each nanotube with particles becomes the catalyst. Our task is to distribute the particles inside the nanotubes and to organise special interactions between them that will provide a high catalytic activity in the oxidation of harmful substances," he said.
"It is assumed that the catalyst obtained in the form of powder or granules can be put into air-cleaning devices in homes, offices or production halls," Mamontov said.

"In this case, it is not necessary to heat it, because this catalyst, in contrast to many analogues, is active and stable at room temperature," he said.
This catalyst will primarily be effective against carbon monoxide and formaldehyde, but can also degrade other harmful, volatile substances into harmless components, researchers said.
"First of all, such a catalyst will be in demand in industrial areas and cities to fight industrial emissions and smog from forest fires, which also contains a large amount of carbon monoxide," said Mamontov.
"In addition, the catalyst can be adapted to neutralise the gas discharges of chemical plants and the exhaust systems of automobiles," he said.