Synthesis of TiO₂-Modified Carbon Aerogel Photocatalysts and Their Application for Removing Formaldehyde in Air

Following the development demand for photocatalytic materials that are available, economical, and active in mild conditions, this work presents an investigation on the way to enhance the photocatalytic activity of TiO₂ towards formaldehyde degradation (HCHO) using carbon aerogel (CA) as a support material. Hereby, composites nTiO₂/(1−n)CA-t_c, where n – the mass ratio of TiO₂ precursor and CA (n = 0.5, 0.7, 0.8, and 0.9); t_c – the experimental calcination temperature (t_c = 400, 500, 600, and 700°C), were synthesised by the solvothermal method. As a relevant result, the CA component was found to be in its amorphous form, while TiO₂ existed in both anatase and rutile phases, which were finely dispersed on the composite surface. The unit cell volume (V_c) of the anatase structure and its average crystallite size (D) varied depending on t_c and n, and so did the corresponding samples’ photocatalytic performance. It was discovered that the sample 0.5TiO₂/0.5CA-400 showed the highest HCHO conversion (x_HCHO) compared to the other synthesised ones, with x_HCHO ≈97% after a conversion time of 75 min. The enhanced activity of 0.5TiO₂/0.5CA-400 was due to its higher V_c (~137.2520 nm³) and lower D (~6.7 nm), which was predicted to have a higher specific surface area. Thus, this study has confirmed the effectiveness of developing TiO₂ photocatalysts based on the CA substrate for HCHO oxidation and exhibited the potential to extend the application to other volatile organic compounds (VOCs).