Soot template TiO2 fractals as a photoactive gas sensor for acetone detection

Using candle soot fractal-like structures as a template to introduce porosity, TiO2 surfaces with visible-blind photoactivity for acetone gas sensing applications were developed, which would otherwise be impossible with thin films of TiO2 formed by chemical vapor deposition (CVD). The photoactivity performance was obtained at low operating potentials, with a high UV response repeatability (∼99%) even towards low UV intensities of μW·cm−2, thus making it suitable for light-assisted gas sensing applications. The acetone gas sensing functionality can be used for non-invasive diabetic diagnoses as the sensing mechanism takes advantage of the developed material’s photoactivity, thus enhancing both sensitivity and selectivity towards acetone gas. This enables the sensor to discriminate between acetone concentrations associated with both healthy and diabetic concentrations in human breath while exhibiting a repeatability and detection limit of >97% and 10 ppb, respectively. The excellent performance is attributed to the high film porosity and fractal like network structures, thus enhancing the number of gas-solid interactions as well as having titania crystalline structure with good optical excitement in the UV range.