Enhanced Mesostructural Order and Changes to Optical and Electrochemical Properties Induced by the Addition of Cerium(III) to Mesoporous Titania Thin Films

Abstract

The addition of up to 10 mol % cerium(III) during the synthesis of cubic mesoporous titania thin films significantly increases the degree of mesostructural order in the final material. Photocurrent measurements, cyclic voltammetry, and spectroelectrochemistry show that the addition of cerium introduces a large number of interfacial states into the mesoporous material, which act as electron traps. Electron trapping by individual cerium ions also causes changes in the electrochemical properties of the mesoporous films. The mesoporous cerium-doped titania films show an increased electrochromic response that is indicated by an increase in absorbance at 550 nm with respect to pure titania. This effect is counter to the behavior of sol−gel ceria−titania films, which generally show a loss of electrochromism compared to pure titania.

Block copolymer-templated synthesis of highly organized mesoporous TiO2-based films and their photoelectrochemical applications

“…Stucky's group [93,109,110] developed a generalized sol-gel system composed of acetic acid, aqueous HCl, ethanol, and metal alkoxides suitable for the synthesis of mesoporous mixed metal oxides. Metal precursors were bound by acetic acid with the formation of the meta-stable complexes under a moisture condition.…”

“…Up to now highly organized mesoporous films of rare-earthmetal ion-doped TiO 2 [109,110], metal or bimetal coupled TiO 2 [52,111], mixed metal oxide such as Nb 2 O 5 /TiO 2 [112], WO 3 /TiO 2 [91,113,114], and Al 2 O 3 /TiO 2 [115], chalcogenide (CdS, CdSe) mixed with TiO 2 [93,106], and multiple metal oxides such as NiTiO 3 , SrTiO 3 and Co 0.15 Ti 0.85 O 1.85 [39,116] have been successfully prepared by the one-pot route. The multicomponent system often enhances the thermal stability of mesoporous structure, because suitable amount of introduced metal precursor mixed with Ti precursor at the atomic level in the initial sol solution can form homogenously mixed oxides or be doped into the crystal lattice of the TiO 2 , which significantly retards the phase transform and crystal growth of TiO 2 [114].…”

Structural, optical, and magnetic study of Ni-doped TiO2 nanoparticles synthesized by sol–gel method

“…There exist various methods of producing titania nanoparticles, such as sol-gel process, electrochemical coating, hydrothermal process, hydrolysis, microemulsion method, thermolysis, flame aerosol process, chemical vapor deposition, etc. [27][28][29][30][31][32][33][34][35]. Sol-gel method is often employed as it offers the advantages such as precise control over the stoichiometry, low-temperature synthesis, high crystallinity, and high purity [36][37][38].…”

Organosilica Monoliths with Multiscale Porosity: Detailed Investigation of the Influence of the Surfactant on Structure Formation

“…The pore walls may, for example consist of silica [3], organosilica [4] and metal oxides [5,6], sulfides [7] or phosphates [8]. Because of their well-defined porous structures a wide range of possible applications exists, for example in the field of separation chemistry, drug delivery or as catalyst supports.…”