Controlled Carbon Doping in Anatase TiO 2 (101) Facets: Superior Trace-Level Ethanol Gas Sensor Performance and Adsorption Kinetics

Abstract

A facile mild thermal decomposition method is adopted to synthesize carbon-doped TiO 2 (C-TiO 2 )(101) facets for development of highly performance ethanol gas sensor with low power consumption at reducing working temperature. Controlled carbon doping provides a favorable pathway for constructing more oxygen vacancies and active functional groups on the TiO 2 surface. The estimation of work functions based on Kelvin probe force microscopy reveals that there is a significant change in the energy band states during controlled carbon doping on TiO 2 . Both substitutional and interstitial carbon doping in TiO 2 lattice introduce more surface active sites which significantly enhance the ethanol gas sensing performance (34.8%) compared to undoped TiO 2 (8.5%) with rapid response/recovery time (2 and 2.8 s) at reduced operating temperature (150 °C) and possess negligible noise to signal ratio. The interfacial reaction mechanism between the ionosorbed species during ethanol gas sensing demonstrates that presence of ionosorbed oxygen species and oxygen vacancies formed in the anatase TiO 2 lattice during C-doping is found to have profound roles in the redox reactions. Carbon doping in TiO 2 lattice can be therefore considered as an effective method for the fabrication of gas sensors with pronounced sensing performances at reduced working temperature for real-time applications.