Room temperature formaldehyde sensor with enhanced performance based on reduced graphene oxide/titanium dioxide

Reduced graphene oxide/titanium dioxide (rGO/TiO2) layered film deposition on the interdigital electrode substrate has been developed through simple thermal treatment for trace detection of formaldehyde (HCHO) at room temperature. The layered film was characterized by UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy, and the formaldehyde sensing performances of rGO/TiO2 layered film were investigated over low detection concentrations from 0.1 ppmv to 0.5 ppmv. An interesting abruption behavior of rGO sheets during the heating process was observed and discussed. However, the dissociation of rGO honeycomb network was prevented for rGO/TiO2 layered film upon elevated temperature, which might be induced by the synergetic interaction between TiO2 nanoparticles and graphene sheets effectively. The sensing-test results revealed that the rGO/TiO2 sensor exhibited rapid response, excellent selectivity, good reproducibility and remarkable sensitivity of 0.8 ppmv(-1), which was higher than that of rGO-based one (0.5 ppmv(-1)). Furthermore, the formaldehyde-sensing mechanism was analyzed based on the combination of catalytic reactions and supporting function of TiO2 nanoparticles. (C) 2015 Elsevier B.V. All rights reserved.