Nanowires useful as heterogeneous catalysts are provided. The nanowires catalysts are useful in a variety of catalytic reactions, for example, the oxidative coupling of methane to ethylene. Related methods for use and manufacture of the same are also disclosed.

A process for preparing a mesoporous material, e.g., transition metal oxide, sulfide, selenide or telluride, Lanthanide metal oxide, sulfide, selenide or telluride, a post-transition metal oxide, sulfide, selenide or telluride and metalloid oxide, sulfide, selenide or telluride. The process comprises providing an acidic mixture comprising a metal precursor, an interface modifier, a hydrotropic or lyotropic ion precursor, and a surfactant; and heating the acidic mixture at a temperature and for a period of time sufficient to form the mesoporous material. A mesoporous material prepared by the above process. A method of controlling nano-sized wall crystallinity and mesoporosity in mesoporous materials. The method comprises providing an acidic mixture comprising a metal precursor, an interface modifier, a hydrotropic or lyotropic ion precursor, and a surfactant; and heating the acidic mixture at a temperature and for a period of time sufficient to control nano-sized wall crystallinity and mesoporosity in the mesoporous material. Mesoporous materials and a method of tuning structural properties of mesoporous materials.

Rare earth compound particles are prepared by a step of heating an aqueous solution containing rare earth metal ions and urea to form a rare earth compound by a reaction of a hydrolysis product of urea, and the rare earth metal ions. In the heating step, heating the aqueous solution into which an acetylene glycol-ethylene oxide adduct is added.

A slurry of a dispersion medium and rare earth oxide particles. The particles having a volume basis median particle size D50 of up to 50 nm. The rare earth oxide particles having a dispersity index S of up to 1, the dispersity index S being determined according to the formula (1):
(D90D10)/D50(1) wherein D10, D50 and D90 are cumulative 10%, 50% and 90% diameters in volume basis particle size distribution, respectively.

A slurry of a dispersion medium and rare earth oxide particles. The particles having a volume basis median particle size D50 of up to 50 nm. The rare earth oxide particles having a dispersity index S of up to 1, the dispersity index S being determined according to the formula (1):
(D90D10)/D50(1) wherein D10, D50 and D90 are cumulative 10%, 50% and 90% diameters in volume basis particle size distribution, respectively.

A metal-supported material including a transition metal excluding Group 4 elements supported on a binary composite oxide. The composite oxide includes a metal element expressed by A.sub.nX.sub.y, where A represents a lanthanoid that is in a partially or entirely trivalent state, X represents an element that is a Group-2 element in a periodic table selected from the group consisting of Ca, Sr, and Ba, or a lanthanoid, and that is different from A, n satisfies 0<n<1, y satisfies 0<y<1, m satisfies 0?m<1, and n+y=1. The composite oxide includes a solid solution that is a tetragonal crystal or a cubic crystal, and a ratio of a value (D.sub.ads) of a dispersion degree of the transition metal obtained by an H.sub.2 pulse chemical adsorption method to a value (D.sub.TEM) of the dispersion degree predicted from an average particle diameter of particles of the transition metal obtained from a TEM image satisfies 0<D.sub.ads/D.sub.TEM<1.

A metal-supported material including a transition metal excluding Group 4 elements supported on a binary composite oxide. The composite oxide includes a metal element expressed by A.sub.nX.sub.y, where A represents a lanthanoid that is in a partially or entirely trivalent state, X represents an element that is a Group-2 element in a periodic table selected from the group consisting of Ca, Sr, and Ba, or a lanthanoid, and that is different from A, n satisfies 0<n<1, y satisfies 0<y<1, m satisfies 0?m<1, and n+y=1. The composite oxide includes a solid solution that is a tetragonal crystal or a cubic crystal, and a ratio of a value (D.sub.ads) of a dispersion degree of the transition metal obtained by an H.sub.2 pulse chemical adsorption method to a value (D.sub.TEM) of the dispersion degree predicted from an average particle diameter of particles of the transition metal obtained from a TEM image satisfies 0<D.sub.ads/D.sub.TEM<1.

An anticorrosive pigment comprising an aluminum polyphosphate comprises at least one cerium-based compound and/or one lanthanum-based compound and/or one praseodymium-based compound. An anticorrosive paint incorporating the pigment is also provided.

A method of recovering metal compounds from solid oxide fuel cell scrap includes processing the solid oxide fuel cell scrap to form a powder, digesting the processed scrap, extracting lanthanum oxide and cerium oxide from a solution containing the digested processed scrap, extracting a zirconium compound from the solution after extracting the lanthanum oxide and cerium oxide, and extracting scandium compound from the solution extracting the zirconium compound from the solution.

A process for separating rare earth elements (REE) from Ca, Mg and other non-REE elements comprises raising the pH of an acidic aqueous solution of REE to pH 8 to pH 11; adding nano- or micro (NoM) particles having a silica or titanium oxide surface; agitating the suspension for 6 h to 48 h to provide for adherent crystallization of REE hydroxide on the particles; separating the particles from the solution; releasing REE by treatment with aqueous acid to form an aqueous solution of REE salt; separating them from the aqueous solution of REE salt formed. The acidic aqueous solution comprising REE is preferably provided by leaching of an REE mineral with aqueous acid; adding a base to bring the pH to from pH 4.0 to pH 6.5; separating precipitated non-REE hydroxide from the solution.