Protonic titanate derived from Cs_xTi_2−x/2Mg_x/2O₄(x = 0.7) with lepidocrocite-type layered structure

Lepidocrocite-like ferrititanate nanosheets and their full exfoliation with quaternary ammonium compounds

“…It is concluded that Ti 4+ /Fe 3+ ratio was kept practically unchanged after the acid exchange reaction, differently from some other correlated LTs compounds such as Cs x Ti 2 − x/2 Mg x/2 O 4 [3] and Cs x Ti 2 − x/2 Zn x/2 O 4 [4] which lost Mg 2+ and Zn 2+ almost completely during the acid exchange, leaving vacancies behind them. The absence of Fe 3+ leaching from the puckered, negatively charged, host layers would be expected since the acid exchange reaction (the exchange of Na + for H + ) was completed in few hours, while for LTs with micronic lateral dimensions such as in the cases of Cs x Ti 2 − x/2 Mg x/2 O 4 [3] and Cs x Ti 2 − x/2 Zn x/2 O 4 [4], synthesized by solid-state reaction, the acid exchange reactions were accomplished after several days. Fig.…”

“…This crystal structure (Fig. S1, Supplementary file) is built from dense, negatively charged, puckered layers consisted of edge shared distorted Ti 1 − x M x O 2 octahedra, whereas the charge neutrality is maintained by alkaline cations situated inside the off-centered rectangular prism sites within open spaces (galleries) formed between dense layers [1][2][3][4]. The occupancy of these sites by alkaline cations is maintained at about 70%.…”

Lepidocrocite-type Layered Titanate Structures: New Lithium and Sodium Ion Intercalation Anode Materials

“…These values give an indication of the tendency for materials to take up bulky guest species such as large ions, solvents, or water. 16 The value of about 3.5 nm -2 for the subject materials in this study suggest that they have a stronger propensity to undergo these processes than Na 2 Ti 3 O 7 , which has a charge density of 5.75 nm -2 , but weaker than that of smectite clays (~1.7 nm -2 ), which readily swell and exfoliate in water. The concept of charge density has important implications for the observed physical and electrochemical properties of the lepidocrocites, which will be discussed later.…”

“…They comprise a large class of isomorphous compounds with composition A x Ti 2-y M y O 4 , where A= K, Rb, or Cs, and M represents a vacancy or Li, Mg, Co, Ni, Cu, Zn, or Mn. 15,16,17,18 Lepidocrocite titanates usually crystallize in an orthorhombic structure, consisting of two-dimensional layers of edge and corner sharing octahedra with the large alkali metal ions (A) located in the interlayers. These compensate for the negative charges that arise from the substitution of low valency metal ions or vacancies (M) for Ti 4+ .…”

Fe-doped and ZnO-pillared titanates as visible-light-driven photocatalysts

“…Recently, layered semiconductor materials have been widely used as catalysts and catalyst supports, derived from their good chemical stability, high specific surface areas, unique cation exchange, semiconducting and swelling properties [4,5]. Of these compounds, lepidocrocite titanates are a popular layered transition metal oxide material with versatile composition, in which cesium titanate can be delaminated into 2D molecular single sheets (i.e., titanate nanosheets) and has been used as a starting material to prepare pillared nanocomposites [6][7][8][9]. It has been demonstrated that cesium titanate has similar physical and chemical properties to TiO 2 such as high resistance to photoinduced corrosion [2].…”