Relationship between interlayer hydration and photocatalytic water splitting of A′1−xNaxCa2Ta3O10·nH2O (A′=K and Li)

✍ Scribed by Tomohiro Mitsuyama; Akiko Tsutsumi; Sakiko Sato; Keita Ikeue; Masato Machida

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 416 KB
• Volume: 181
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1016/j.jssc.2008.03.020

✦ Synopsis

Partial replacement of alkaline metals in anhydrous KCa 2 Ta 3 O 10 and LiCa 2 Ta 3 O 10 was studied to control interlayer hydration and photocatalytic activity for water splitting under UV irradiation. A 0 1Àx Na x Ca 2 Ta 3 O 10 Á nH 2 O (A 0 ¼ K and Li) samples were synthesized by ion exchange of CsCa 2 Ta 3 O 10 in mixed molten nitrates at 400 1C. In K 1Àx Na x Ca 2 Ta 3 O 10 Á nH 2 O, two phases with the orthorhombic (C222) and tetragonal (I4/mmm) structures were formed at xp0.7 and xX0.5, respectively. Upon replacement by Na + having a larger enthalpy of hydration (DH h 0 ), the interlayer hydration occurred at xX0.3 and the hydration number (n) was increased monotonically with an increase of x. Li 1Àx Na x Ca 2 Ta 3 O 10 Á nH 2 O showed a similar hydration behavior, but the phase was changed from I4/mmm (xo0.