Mesoporous Monocrystalline TiO₂ and Its Solid-State Electrochemical Properties

Abstract

Mesoporous monocrystalline rutile TiO 2 has been fabricated at low temperature using mesoporous silicas SBA-15 and KIT-6 as hard templates. The key step of the synthetic process was introducing titanium nitrate complex into the template pores and allowing it to dry, dehydrate, decompose, and finally, form TiO 2 crystals in the pores. It was found that the reaction temperature and concentration of HNO 3 in the used precursor had great effects to the crystallization of TiO 2 . Removal of the silica templates after the TiO 2 crystallization has been investigated. Crystallization of TiO 2 in cage-containing mesoporous silicas, FDU-12 and SBA-16 was not successful, further confirming the previous speculation about strong interaction between the crystals and the wall of silica cages. The porous titanium oxide specimens were characterized by using various techniques, including XRD, HRTEM, and nitrogen adsorption/desorption. Proton conductivity and Li-ion insertion property of the samples were also examined. The highest conductivity, 8 × 10 -3 S cm -1 , was obtained at 50 °C under 100% RH and 1 Li + could be accommodated per TiO 2 unit (335 mA h/g) for the first discharge.

Synthesis of TiO2 with diverse morphologies as supports of manganese catalysts for CO oxidation

“…This worm-like structure is sometime more stable than ordered structure, which is already shown in Table 1, the above results well agree with what is mentioned in early literature [21,22]. As described in the literature previously [23], HT sample shows a partial regular and replicated structure. The particles of RU samples are huge and relatively independent, which coincides with its large crystallite size (Table 1).…”

Syntheses, Li Insertion, and Photoactivity of Mesoporous Crystalline TiO2

“…[21] In the present study, photocatalytic activity and Li-storage capability of the new porous TiO 2 products are investigated in comparison with the previous results from other TiO 2 materials, including porous TiO 2 templated by mesoporous silica KIT-6. [22] …”

Mesoporous Titania: Synthesis, Properties and Comparison with Non-Porous Titania

“…Such problem has been successfully overcome by Yue et al [27]: they prepared M-TiO 2 -negative replicas of both SBA-15 and KIT-6 mesoporous silica by pre-hydrolysing the Ti 4 ) and dissolving it in HNO 3. The so-obtained acidic solution of Ti nitrate complexes was used for the infiltration step.…”

“…The so-obtained acidic solution of Ti nitrate complexes was used for the infiltration step. Another interesting result was the formation of rutile M-TiO 2 at calcination temperatures as low as 100°C, ascribed to either the confinement effect [27] of KIT-6 mesoporous channels or the ability of nitrate ions to stabilise the rutile phase within the SiO 2 walls. Indeed, when other Ti precursors are employed (like chloride, sulphate and isopropoxide), anatase M-TiO 2 preferentially forms and transition to rutile M-TiO 2 is not observed at temperatures as high as 600°C [28].…”