Characterization and activity of mesoporous titanium dioxide beads with high surface areas and controllable pore sizes

Abstract

Mesoporous titanium dioxide beads with high surface areas (over 90 m 2/g) and tunable pore sizes (from 12.8 to 16.5 nm) were synthesized via a solvothermal process heating by microwave irradiation, with ammonia being used as both a source of nitrogen and a control agent for the mesoporous structure. Structural characterization indicated that the mesoporous TiO 2 beads were composed of nanocrystals and pores and the beads possess a optical band gap energy of 3.11 eV. The doping nitrogen was in the form of NH x or NO x species and was adsorbed on surface of the beads, which caused changes to the surface electronic structure. The results show that the samples which possess higher-order structure, large surface area and well-defined crystallinity have the best performance in photocatalytic activities exhibited as evaluated in the degradation of methylene blue.