Photocatalytic sensor of organics in water with signal of plasmonic swing

Photocatalytic oxidation of organics in water is imperative to exploit for environmental analysis due to its green and low-cost advantages. Driven by the visible light, metal nanoparticles exhibit local surface plasmons (so called nanoplasmons), providing a simple and sensitive optical transduction of the electron density surrounding the particles, in addition to enhancing the photocatalytic activity. Thereof, a novel photocatalytic sensor for the detection of organics was proposed using a nanocomposite film consisting of gold and titania nanoparticles and fullerene (Au-TiO 2 -C 60 ), where gold nanoparticles were introduced as both the co-catalyst and the plasmonic sensor. In the redox reaction, the repeated shifts of the nanoplasmonic peak of gold nanoparticles, as a result of the electron transfer mediated by gold nanoparticles, was observed using surface plasmon spectroscopy. The frequency of the plasmonic swing reflects the reaction rate and was used to determine the concentration of organics in water. A response background close to zero provides the sensor with a high precision and a high sensitivity, offering a great potential of the plasmonic sensor in practical applications.