Study on ESR and inter-related properties of vacuum-dehydrated nanotubed titanic acid

Nanotubed titanic acid (H2Ti2O4(OH)2) is a novel kind of material. The electron spin resonance (ESR) and inter-related properties of its vacuum-dehydrated product were investigated by means of transmission electron microscopic, X-ray diffraction, ESR, diffuse reflectance spectra. The results showed that after treatment under vacuum (-0.1 MPa) at 100 degree sign C, single-electron-trapped oxygen vacancies (SETOV), characterized by a symmetrical ESR signal (g=2.003), were generated in nanotubed H2Ti2O4(OH)2 crystal lattice. The g=2.003 ESR signal intensity (IESR) increased with treatment time. SETOV played the role of F centers, the visible-light absorption power of vacuum-dehydrated H2Ti2O4(OH)2 was proportional to IESR. During vacuum dehydration at 100 degree sign C, the H2Ti2O4(OH)2 nanotubes shortened but its crystalline form kept unchanged. The formation mechanism of SETOV was discussed