Gold-Plated Church Windows Purify Air

Medieval stained-glass windows colored in gold nanoparticles help purify air when lit by the sun, a new study finds.

"For centuries people appreciated only the beautiful works of art, and long life of the colors, but little did they realize that these works of art are also, in modern language, photocatalytic air purifier with nanostructured gold catalyst," said Zhu Huai Yong, a material scientist at the Queensland University of Technology.

When energized by the sun, tiny gold particles can destroy certain airborne pollutants. These pollutants, called volatile organic compounds, create the "new" smell often detected in new furniture, carpets and paint in good condition. Even in small amounts, these compounds, like methanol and carbon monoxide, are not good for your health.

An electromagnetic field generated by sunlight couples with the gold electrons' oscillations to create a resonance, said Zhu. The magnetic field of the gold nanoparticles can expand up to hundred times, breaking apart the pollutant molecules.

Zhu said the byproduct of the reaction is carbon dioxide, which is comparatively safe, particularly in the small amounts that would be created through this process.

The high price of gold notwithstanding, using gold nanoparticles to drive these chemical reactions is more energy-efficient than conventional air-purifying processes, the researcher says, and it might be possible to commercialize it.

"Once this technology can be applied to produce specialty chemicals at ambient temperature, it heralds significant changes in the economy and environmental impact of the chemical production," said Zhu.

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