Low-temperature synthesis of nanometer-sized crystalline TiO2 particles and their photoinduced decomposition of formic acid

Anatase TiO2 particles with an average size of 2.7 nm in an as-grown state were obtained below 373 K from an H2O-EtOH mixed solution of TiOSO4 by a fa cile liquid phase method. The volume ratio of H2O to EtOH was revealed to b e the key for crystallinity of the particles, The as-grown particles prepar ed from the H2O-EtOH solution (H2O/EtOH (mL/mL) = 150/100) showed a high ph otoreactivity in the TiO2 photoinduced decarboxylation of HCOOH under a dea erated condition. In contrast, under an aerated condition, the rate of the reaction increased with an increase in calcining temperature (T-c) due to t he improvement of anatase crystallinity, going through a maximum at T-c = 8 73 K. (C) 1999 Academic Press.