New layered double hydroxide materials useful as intermediates in the formation of catalysts are described, as well as methods of preparing the layered double hydroxides. Also described are catalysts suitable for catalysing the hydrogenation of CO.sub.2 to methanol, as well as methods for preparing the catalysts. The LDH-derived catalysts of the invention are active in the hydrogenation of CO.sub.2 to methanol, and show improved activity with respect to Cu/ZnO catalysts derived from copper-zinc hydroxycarbonate precursors.

Provided is a layered double hydroxide membrane containing a layered double hydroxide represented by the formula: M.sup.2+.sub.1-xM.sup.3+.sub.x(OH).sub.2A.sup.n.sub.x/n.mH.sub.2O (where M.sup.2+ represents a divalent cation, M.sup.3+ represents a trivalent cation, A.sup.n represents an n-valent anion, n is an integer of 1 or more, and x is 0.1 to 0.4), the layered double hydroxide membrane having water impermeability. The layered double hydroxide membrane includes a dense layer having water impermeability, and a non-flat surface structure that is rich in voids and/or protrusions and disposed on at least one side of the dense layer. The present invention provides an LDH membrane suitable for use as a solid electrolyte separator for a battery, the LDH membrane including a dense layer having water impermeability, and a specific structure disposed on at least one side of the dense layer and suitable for reducing the interfacial resistance between the LDH membrane and an electrolytic solution.

Layered double hydroxides (LDHs) are disclosed, as well as methods by which they may be manufactured. The LDHs are subjected to a solvent treatment step during manufacture, which confers high surface area and pore volume properties to the LDHs. The particular solvents used in the preparation of the LDHs renders allows for an overall more efficient and environmentally-friendly manufacturing process.

A phosphor contains a crystal phase having a chemical composition Ce.sub.xM.sub.3-x-y.sub.6.sub.11-z. M is one or more elements selected from the group consisting of Sc, Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. contains Si in an amount of 50 mol % or more of a total mol of . further contains Al. contains N in an amount of 80 mol % or more N of a total mol of . x satisfies 0<x0.6. y satisfies 0y1.0. z satisfies 0z1.0.

There is provided a functional layer including a layered double hydroxide. The functional layer further contains titania.

There is provided a functional layer including a layered double hydroxide, which is composed of: a plurality of basic hydroxide layers including Ni, Al, Ti, and OH groups; and intermediate layers composed of anions and H.sub.2O, each intermediate layer being interposed between two adjacent basic hydroxide layers.

There is provided a functional layer including a layered double hydroxide. The layered double hydroxide does not undergo a change in the surface microstructure and the crystalline structure when immersed in 5 mol/L of an aqueous potassium hydroxide solution containing zinc oxide in a concentration of 0.4 mol/L at 70 C. for three weeks.

There is provided a functional layer including a layered double hydroxide that contains Ni, Al, Ti and Zn, and has an atomic ratio Zn/(Ni+Ti+Al+Zn) of 0.04 or more determined by an energy dispersive X-ray analysis (EDS).

There is provided a functional layer including a layered double hydroxide (LDH). The functional layer includes a first layer with a thickness of 0.10 m or more, the first layer being composed of fine LDH particles having a diameter of less than 0.05 m, and a second layer composed of large LDH particles having a mean particle diameter of 0.05 m or more, the second layer being an outermost layer provided on the first layer.

There is provided a functional layer including layered double hydroxide. The functional has an average porosity of 1 to 40% and an average pore diameter of 100 nm or less.