K, Na and Cl co-doped TiO2 nanorod arrays on carbon cloth for efficient photocatalytic degradation of formaldehyde under UV/visible LED irradiation

Abstract

For applicable air purifiers to decompose formaldehyde, it is important to develop TiO₂ based photocatalysts that can be irradiated under visible light and can be anchored on a soft carbon cloth substrate. Herein, we report that rutile TiO₂ nanorod arrays were grown on carbon cloth (TiO₂@CC) by a seed assisted hydrothermal method and subsequently heated with a KCl and NaCl covering to promote K, Na, and Cl ions doping into the TiO₂ nanorods. K, Na, and Cl doping tunes the energy band structure of rutile TiO₂, while the carbon fibers facilitate the electron transfer, improving its photocatalytic activity. Thus, the alkali metal (K, Na) and halogen (Cl) co-doped rutile TiO₂ nanorod arrays (KNCTC) exhibited better photocatalytic degradation of gaseous formaldehyde (HCHO) under UV and visible light irradiation than pure TiO₂. TiO₂ nanorod arrays anchored on soft carbon cloth facilitate the design of an air purifier for degrading formaldehyde.