One-step fabrication of TiO2/Ti foil annular photoreactor for photocatalytic degradation of formaldehyde

One-step hydrothermal synthesis approach is applied to prepare oriented TiO2 nanowires on a Ti foil which serves as both the substrate and Ti source. The grown TiO2 nanowires are characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffractometry. The adsorption and photocatalytic performance of the TiO2/Ti foil catalyst in formaldehyde degradation has been explored in detail by a homemade setup, aiming at elucidating the photocatalytic performance of the TiO2/Ti foil catalyst as functions of the experimental preparation parameters, such as NaOH concentration, hydrothermal reaction temperature and time elapse as well as post-annealing temperature. More strikingly, the TiO2/Ti foil catalyst can be directly devised into a self-supporting annular reactor which is at least twice as efficient for the formaldehyde degradation as that based on commercial TiO2 powder catalyst. This study presents a scalable and commercially viable strategy for indoor air purification.