Biomorphic Carbon-Doped TiO₂ for Photocatalytic Gas Sensing with Continuous Detection of Persistent Volatile Organic Compounds

How to protect the sensitivity of gas sensing system in the case of persistent leakage in a closed environment? The aim of this study is to combine the gas sensing property of semiconductor with its photocatalytic performance, which may be viable alternative to give recovery time to gas sensors in the closed environment. By using Papilioparis butterfly wings as biotemplates, we herein demonstrate a facile way to synthesize biomass carbon doped TiO2 with the replication of quasi-honeycomb scales structures, which is beneficial to highest specific area (85.27 m2·g–1) in comparison with pure TiO2 and Ag-doped TiO2. The biomorphic C/TiO2 exhibit not only excellent responses to benzene and dimethylbenzene vapors at 300 °C operating temperature superior to that of Ag-doped TiO2, but also have excellent sensitivity to visible light. Furthermore, the multifunctional biomorphic C/TiO2, used as safe concentration detectors, could determine vapors concentrations by gas sensing response values. Adopting illuminating the photocatalysts in the closed environment, the responses to dimethylbenzene and benzene have almost no changes along with continuous vapors injection. This work shows a good example for exploring the integrated application of semiconductor materials and improving the gas sensors lifetime.