Adsorption and photocatalytic oxidation of formaldehyde on a clay-TiO2 composite

► Formaldehyde adsorption and photocatalytic elimination on hectorite-TiO2 nanocomposites. ► Dark adsorption in dry air >4 times higher than P25 (reference). ► Dark adsorption in humid air dominated by adsorbed water layer. ► Photocatalytic removal efficiency proportional to the Ti content, increased with contact time. ► More complete elimination with 254 + 185 nm irradiation.