The crystal structures and microstructures of precipitates formed in an Mg-0.5 at%Nd alloy aged at certain temperatures ranging between 170 C and 250 C are studied in detail by high-angle annular detector dark-field scanning transmission electron microscopy. The precipitation sequence can be presented as Mg-solution ! GP-zone ! 0 (orthorhombic) ! 1 (fcc). At the early stage of aging (170 C for 2 h), fine precipitates of planar GP-zones appear in parallel to (100) m planes, with a thickness of sub-nm and a length of 5-15 nm (the subscript letter of m denotes matrix). With an advance of aging, the GP-zones increasingly grow larger and combine with the neighbours, thus making themselves further prolonged along the directions addressed above. When reaching at the top-stage of aging (170 C for 100 h), the alloy additionally allows the 0 -phase to coexist, taking the form of lens-shape with a thickness of 2-5 nm and a diameter of 5-15 nm. The 0 -phase has an orthorhombic structure (Mg 7 Nd) with a ¼ 0:64 nm, b ¼ 1:1 nm, and c ¼ 0:52 nm, which is coherently connected to the matrix. At the stage of over-aging, both the GP-zones and the 0 -phase disappear and instead coarse precipitates of the stable 1 -phase (Mg 3 Nd; fcc) are formed with particular crystallographic relations of ½001 m == ½110 p and ½110 m == ½112 p (the subscript letter of p denotes precipitate).

The immobilization of functional units in the interlayer spaces of layered silicates and titanates is summarized from the viewpoint of how the spatial distribution of functional units in the interlayer affects the performance of the intercalation compounds. The ways of incorporating controlled amounts of functional units with controlled spatial distribution are also discussed. As a result of controlled spatial distribution of functional units in two-dimensional nanospace, one can achieve improved efficiency of photo-induced events (photoluminescence and photoinduced electron/energy transfer), molecular sieving and substrate/product selective catalytic reactions.

Although tremendous effort has been directed to synthesizing advanced TiO2 , it remains difficult to obtain TiO2 exhibiting a photocatalytic efficiency higher than that of P25, a benchmark photocatalyst. P25 is composed of anatase, rutile, and amorphous TiO2 particles, and photoexcited electron transfer and subsequent charge separation at the anatase-rutile particle interfaces explain its high photocatalytic efficiency. Herein, we report on a facile and rational hydrothermal treatment of P25 to selectively convert the amorphous component into crystalline TiO2 , which is deposited between the original anatase and rutile particles to increase the particle interfaces and thus enhance charge separation. This process produces a new TiO2 exhibiting a considerably enhanced photocatalytic efficiency. This method of synthesizing this TiO2 , inspired by a recently burgeoning zeolite design, promises to make TiO2 applications more feasible and effective.

We report a methodology for creating protonated layered titanate-rutile heterojunctions on the outer particle surface of protonated layered titanate by treating layered potassium titanate (KTiLiO) with dilute HCl and then drying it at room temperature under reduced pressure. After Pt co-catalyst loading, this protonated layered titanate/rutile composite with heterojunctions showed higher photocatalytic H evolution activity from water under simulated solar light compared to that of Pt-loaded P25, the standard photocatalyst for this reaction. The high photocatalytic activity was ascribable to enhanced photocatalytic activity of the protonated layered titanate based on an efficient charge separation at the protonated layered titanate-rutile heterojunction in addition to the sensitization effects of rutile, which absorbs light with longer wavelengths compared to those of protonated layered titanate.