Kinetic reconstruction of TiO2 surfaces as visible-light-active crystalline phases with high photocatalytic performance†
Abstract
Modulation of the TiO2 structure to achieve efficient photocatalytic usage of solar light is still a challenging issue. Here we report that simple bombardment of anatase TiO2 nanocrystals by hot molecules can alter its phase transformation kinetics and lead to the reconstruction of the resulting rutile surfaces into a metastable TiO2 crystalline structure. Moreover, the metastable surface crystalline phase is able to harvest visible light up to 480 nm, and exhibits good properties for photocurrent generation. Photocatalysis tests show that upon irradiation by visible light (λ > 420 nm), the surface-reconstructed TiO2 crystals display excellent and stable photocatalytic activity for hydrogen production from aqueous ethanol solution, with a hydrogen production rate of 302 μmol g−1 h−1. This finding might bring a new approach to kinetically tune the structure of TiO2 or other semiconductor crystals in order to modulate their properties.