Nanoporous Metal Foam Filters for Clean Air

Tech ID: 27645 / UC Case 2017-084-0


Researchers at the University of California, Davis have developed nanoporous metal foams as universal pollutant arrestors.

Full Description

Conventional air filters are designed to capture relatively large particulates over 0.3 micron in size, such as pollen and dust particles. Over 90% of all particulates such as those found in smog are in the sub 0.3 micron regime, very fine and ultra-fine aerosols, known as “lung penetrating particles” which pose the most health risks. For such small particles there has been a lack of effective filters. Current filter media with HEPA ratings has such a high pressure drop that air flows are reduced, limiting their ability to clean the air in even modest rooms.

Researchers at the University of California Davis have developed nanoporous metal foams as universal pollutant arresters. Such foams have a host of fascinating electrical, magnetic, mechanical, optical and chemical properties due to their extremely high surface areas, nanoscale constricted geometries, and high porosity. Nanoporous metal foams offer a platform to combat sub-0.3 micron particles (such as smog and air pollution) by combining 1) physical processes such as trapping and electrostatics / ionization to capture particulates; 2) absorption of certain gas into the metal foam; and 3) catalytic reactions to neutralize toxic smog species by using the metal foams as catalysts.

In addition, the use of metallic filter media allow organic analyses by combustion of wet chemistry without the problems of carbon containing substrates. The only other material in common use that has this property, fired quartz filters, has the problem that in the firing process needed for cleaning, F-centers are formed that trap gasses, giving false readings that can often double the actual organic mass in the atmosphere.


  • Air filters and pollutant arresters, particularly for the sub-0.3 micron size regime


  • Efficient for filtering sub-0.3 micron size particulates (known as lung-penetrating particles)
  • Large effective surface areas
  • Advanced method of capturing smog including trapping, absorption and catalytic reaction
  • Scalable and Mass-producible
  • Cost effective
  • Renewable
  • Ultra-lightweight and portable
  • Durable

Related Materials

Patent Status

Country Type Number Dated Case
Patent Cooperation Treaty Reference for National Filings 2018187633 10/11/2018 2017-084

Patent Pending


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  • Liu, Kai

Other Information


air purifier, HEPA filter, porous metal foams, smog, air pollutant arrester

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