Real-time detection of alcohol vapors and volatile organic compounds via optical electronic nose using carbon dots prepared from rice husk and density functional theory calculation

Publication date: Available online 30 September 2018Source: Colloids and Surfaces A: Physicochemical and Engineering AspectsAuthor(s): Nichaphat Thongsai, Nattapong Tanawannapong, Janjira Praneerad, Sumana Kladsomboon, Panichakorn Jaiyong, Peerasak PaoprasertAbstractRice husk, an agricultural waste that currently finds few uses, is rich in cellulose-based materials and silica. In this work, a simple one-pot method for preparing carbon dots and mesoporous silica from rice husk was developed, using hydrothermal and calcination methods. The carbon dots exhibited blue emission with excellent photostability, and had a diameter of 4-5 nm and a quantum yield of 3%. They were demonstrated to be capable of detecting alcohol vapors at room temperature, and of distinguishing between methanol, ethanol, and several volatile organic compounds when used as the sensing layer in an optical electronic nose system. The alcohol content of a commercial beverage was successfully determined using the carbon dot-integrated electronic nose. The solvation effect of the alcohol vapors on the electronic absorption spectra of model carbon dot structures was illustrated using time-dependent density functional theory with the dielectric polarizable continuum model. The UV-vis and computational results confirmed that the sensing mechanism of carbon dots is through the modulation of their optical absorbance governed by polar-polar interfacial interactions. This was experimental and computational demonstrat...

Source: Colloids and Surfaces A: Physicochemical and Engineering Aspects - October 6, 2018 Category: Chemistry Source Type: research