Nanowhiskers of K2Ti6O13 as a promoter of photocatalysis in anatase mesocrystals

Abstract

Here we describe the development of a new mesocrytalline anatase-based photocatalyst with an activity nearly double that of the commercial Evonik Aeroxide® TiO2 P25 catalyst. An extensive characterization of this new catalytic material with XRD, TEM, SAED, EELS, SEM, RAMAN and XPS shows that its activity is promoted by its hybrid structure comprising mesocrystalline anatase and K2Ti6O13 whiskers formed within the TiO2 mesocrystals. This new and unexpected component is formed in situ within the TiO2 mesocrystalline framework at a surprisingly low temperature of 500 °C as a result of potassium diffusion from polymer-matrix phase. The growth of whiskers occurs at the 001 TiO2 planes of mesocrystals and their sizes attain 60 nm in a section and a few μm in length.