Chen presents two talks at the 2013 ACS Northeast Regional Meeting (NERM) in New Haven

October 22, 2013

Silver Nanoparticle Sensors in Art Conservation Applications

Abstract: A color-changing sensor based on silver nanoparticles has been developed for the fast and quantitative detection of H2S gas in museum environments. Sulfide gases may signal deterioration of proteinaceous artifact materials, and building and display materials are often screened (in Oddy tests) for their potential to emit these gases, which are known hazards to collections. Silver nanoparticle sensors have been demonstrated to rapidly detect H2S at concentrations in the parts per million by volume range at ambient conditions. The gas concentration can be determined either from the initial reaction rate or from the extent of reaction after prolonged exposure. Air, water vapor, acetone, ethanol, ammonia and hydrochloric acid do not interfere with detection of H2S at ambient conditions. Silver nanoparticle sensors have also been tested as substitutes for silver foil in Oddy tests, and they can detect sulfide gas emission before silver foils show visible corrosion.

Fast Detection of H2S Gas in ppmv Range with Silver Nanoparticle Films at Ambient Conditions

Abstract: An optical sensor based on silver nanoparticles (Ag NPs) has been designed to detect H2S gas at room temperature. The fabricated Ag NP films were very sensitive to the presence of H2S with a gas concentration in the parts per million by volume (ppmv) range, as indicated by a significant and rapid decrease in the peak absorbance of the localized surface plasmon resonance of Ag NPs. The initial reaction between Ag NPs and H2S gas was revealed to be a first-order reaction in Ag, and the initial reaction rate was proportional to the gas concentration in the ppmv range. The gas concentration can be determined from either the initial reaction rate or from the H2S dose measured after extended reaction periods. Performance of the Ag NP film at ambient conditions was evaluated by exposure to H2S in air, to water vapor, ammonia, hydrochloric acid or some volatile organic compound vapors.

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