The investigation of reduced graphene oxide/titanium dioxide-based sensor for formaldehyde detection at room temperature

Reduced graphene oxide/titanium dioxide (rGO/TiO₂) layered film was firstly utilized through simple spray method for trace detection of formaldehyde (HCHO) at room temperature. A remarkable sensitivity of layered film (0.8 ppm^-1) was identified in the concentration range of 0.1 ppm to 0.5 ppm, which was higher than that of rGO-based sensor (0.5 ppm^-1). It was worth noting that an interesting abruption behavior of rGO sheets during the thermal reduction process was observed. However, the collapse of rGO honeycomb network during temperature-rise period could be prevented due to the introduction of TiO₂ nanoparticles. Furthermore, a novel mechanism based on àie combination of catalytic reactions and supporting function of TiO₂ nanoparticles was introduced to explain the enhanced sensing performance of rGO/TiO₂ layered film in contrast to bare rGO film.