Highly active BaTi4O9/RuO2 photocatalyst by polymerized complex method

Abstract

A polymerized complex (PC) technique was utilized to prepare high-purity barium tetratitanate (BaTi4O9) fine powders at a low temperature (700 °C). BaTi4O9 via the PC route, combined with RuO2, exhibited 2.4 times larger photocatalytic activities for the decomposition of water compared to those for a sample prepared by a solid-state reaction method. A considerably large surface area (∼30 m2/g) of the BaTi4O9/RuO2 powder via the PC route, when compared with ∼5 m2/g for the solid-state reaction powder, was supposed to be one of the key factors responsible for the high photocatalytic activity observed.

Effects of Cocatalyst and Calcination Temperature on Photocatalytic Hydrogen Evolution Over BaTi4O9 Powder Synthesized by the Polymerized Complex Method

“…Powders of BaTi 4 O 9 were synthesized by the PC route according to the procedures in literatures [7,8]. Here Ba(CH 3 COO) 2 instead of BaCO 3 were selected as Ba sources for better solubility and improved interactions between Ba and Ti complexes.…”

“…This unique structure has two distinctive advantages in photocatalytic reactions: (1) the dipole moment resulted from the heavily distorted TiO 6 octahedra are considered to be useful for electron-hole separation upon photoexcitation [12]; (2) the characteristic structure provides the form of a concave site with a ridge like a ''nest'', which likely makes a geometric barrier to prevent the loading cocatalyst from growing and aggregating [2]. Recently, the advantage of Pechini-type polymerized complex (PC) method to the traditional solid-state reaction (SSR) method has been greatly confirmed for the improved crystalline homogeneity and photocatalytic activity of the product [13,14], which is especially meaningful for RuO 2 -BaTi 4 O 9 [7,8], from the aspect that the suppressed growth of unstoichiometric impurities and highly dispersive RuO 2 particles can be achieved by the PC method.…”

“…The compounds of barium titanates are of great importance in materials science due to their attractive ferroelectric and dielectric properties. Special interests have been paid to the photocatalytic applications of these materials with a TiO 2 -rich content, such as BaTi 4 O 9 [6][7][8], BaTi 5 O 11 [9], Ba 4 Ti 13 O 30 [10] and etc. BaTi 4 O 9 combined with RuO 2 has emerged as a new class of potential photocatalyst for photocatalytic water decomposition [6].…”

Synthesis and photocatalytic property of BaTi4O9/RuO2 nanocomposites

“…So, in order to improve the photocatalytic splitting of water abilities, one efficient way may be to develop nanostructured photocatalysts with extremely improved surface areas, because the large surface area can increase active sites at which the photocatalytic reaction occurs or small particle size diminishes the distance of transfer of the photo-generated electrons and holes from the bulk to the surface [8][9][10][11][12][13][14][15]. Kakihana et al have reported the photocatalytic activity for the decomposition of water in the BaTi 4 O 9 /RuO 2 material prepared via the PC route is higher than that in the sample prepared by the conventional solid-state reaction method and suggested that the remarkable increase of the photocatalytic reaction is at least partly attributable to the large surface area of the BaTi 4 O 9 /RuO 2 powder via the PC route [16,17]. Another critical point among the factors affecting the photocatalytic properties is structural anisotropy because of the promotion of charge separation associated with inhibition of the charge recombination process.…”

Enhanced Photocatalytic Hydrogen Evolution Over CaTi1−x Zr x O3 Composites Synthesized by Polymerized Complex Method

“…The crystal structure of CaTiO 3 is, strictly speaking, GdFeO 3 type derived from distorting the ideal cubic perovskite structure [8]. It is known that the BaTi 4 O 9 compound of pentagonal-prism tunnel structure, though bringing about a significantly large distortion of TiO 6 octahedra, exhibits much higher activities in photocatalytic H2 production than the ideal perovskite of BaTiO 3 [9,10]. Therefore, the investigation concerning the photocatalytic activity of CaTiO 3 is important as well as other alkaline earth titanates.…”