Plasmonic-based Detection of NO₂ in a Harsh Environment

The surface plasmon resonance (SPR) band response of Au nanoparticles embedded in yttria-stabilized zirconia (Au-YSZ) nanocomposite films are extremely sensitive to high-temperature catalysis processes. By varying the concentration of NO 2 in air and O 2 in N 2, we show that Au-YSZ nanocomposite films are sensitive to changes in NO 2 concentration in air, with a detection limit of 5 ppm. We also show a linear relation between the change in the equilibrium ratio, p O 2 −1/8 p NO 2 −1/4, contributing to oxygen ion diffusion into and out of the YSZ matrix, and the change in the square of the SPR band peak position, confirming an interpretation of the experimental results using the free electron theory model for the optical properties of metal nanoparticles. Furthermore, we observe that there is a temperature dependence in the sensor response of the Au-YSZ nanocomposite film that has an inverse relation to concentrations of surface adsorbed O − species on the YSZ matrix.