Fullerene (C₆₀) functionalized TiO₂ nanotubes for conductometric sensing of formaldehyde

In the current study, fullerene-C₆₀, functionalized with various oxygen-containing groups, was decorated on a highly oriented electrochemically grown TiO₂ nanotubes array for efficient detection of volatile organic compounds (VOCs) like formaldehyde. Concentrations of C₆₀ were varied to prepare different wt% (0.006, 0.01, 0.02 and 0.05) of fullerene water colloidal systems, which were then used to prepare composite with TiO₂ nanotubes by hydrothermal route. Detailed characterizations were performed to assess the morphology, structure and chemical compositions of the developed nanocomposites. BET analysis was performed to estimate the increased effective surface area due to the inculcation of the fullerene clusters of different sizes to the TiO₂ nanotube surface. C₆₀-TiO₂ nanotubes composite showed natural selectivity towards formaldehyde. Ultra-high sensitivity (99.6%) by 0.05 wt% C₆₀-TiO₂ nanotube and very fast response/recovery (4 s/7 s) by 0.02 wt% C₆₀-TiO₂ nanotube were recorded towards 100 ppm of formaldehyde at 150 °C. The sensors covered the maximum detection range was 100 ppm to 100 ppb. However, highly promising VOCs detection was possible due to the enhanced surface area and high reactive surface provided by the C₆₀-TiO₂ nanotube composites.