Characterization of oxides obtained by heating a mixture of peroxoniobic acid and peroxotitanic acid.
Nb-doped TiO(2) particles were prepared by heating a mixture of peroxotitanic acid and peroxoniobic acid in air. When the heating temperature was more than 1173 K, the dominant phase obtained was rutile TiO(2), along with a small amount of TiNb(2)O(7). The relationship between the lattice parameters of the obtained rutile TiO(2) depended on the molar fraction of Nb/(Ti + Nb). In the case where peroxo compounds were used as a precursor, a change in the lattice parameters of the rutile TiO(2) was observed within the lower X(Nb) range, as compared to the alkoxide method. The results indicate that a homogeneous dispersion of doped Nb(5+) ions in the obtained rutile TiO(2) lattice was achieved by using peroxo compounds. Furthermore, the oxide particles obtained by using peroxo compounds had a lower activation energy of the carrier electrons (E(a)) and oxygen vacancies, even though the heating procedure was carried out in air. The UV-vis absorption spectra and Raman spectra of the obtained oxide particles indicated that the dominant reaction of the decomposition of O(2)(2-) ions in the TiO(2) lattice was O(2)(2-)→ O(2) + 2e(-) as a reducing agent.
Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba-shi 263-8522, Japan. uekawa@faculty.chiba-u.jp
Naofumi
N
Uekawa
Yusuke
Y
Oosawa
Takashi
T
Kojima
Kazuyuki
K
Kakegawa