Doped cerium oxide particles may comprise about 90 weight percent (wt. %) to about 99.9 wt. % cerium oxide (CeO.sub.2) and up to about 10 wt. % dopant. Exemplary doped cerium oxide particles may have a BET specific surface area of more than 150 m.sup.2/g after calcination at 500° C. for 8 hours. Exemplary doped cerium oxide particles may have an oxygen storage capacity (OSC) of more than 900 μmol.Math.O.sub.2/g after calcination at 500° C. for 8 hours.

To a co-precipitating aqueous solution, aqueous solutions containing (a) Tb ions, (b) at least one other rare earth ions selected from the group consisting of Y ions and lanthanoid rare earth ions (excluding Tb ions), (c) Al ions and (d) Sc ions are added; the resulting solution is stirred at a liquid temperature of 50° C. or less to induce a co-precipitate of the components (a), (b), (c) and (d); the co-precipitate is filtered, heated and dehydrated; and the co-precipitate is fired thereafter at from 1,000° C. to 1,300° C., thereby forming a sinterable garnet-type complex oxide powder.

A powder of melted particles, more than 95% by number of the particles exhibiting a circularity of greater than or equal to 0.85. The powder including more than 99.8% of a rare earth metal oxide and/or of hafnium oxide and/or of an aluminum oxide, as percentage by mass based on the oxides. The powder has a median particle size D.sub.50 of less than 15 μm, a 90 percentile of the particle sizes, D.sub.90, of less than 30 μm, and a size dispersion index (D.sub.90−D.sub.10)/D.sub.10 of less than 2, and a relative density of greater than 90%. The D.sub.n percentiles of the powder are the particle sizes corresponding to the percentages, by number, of n %, on the cumulative distribution curve of the size of the particles in the powder and the particle sizes are classified by increasing order.

This invention relates to azirconium hydroxideor zirconium oxide comprising, on an oxide basis, up to 30 wt % of a dopant comprising one or more of silicon, sulphate, phosphate, tungsten, niobium, aluminium, molybdenum, titanium or tin, and having acid sites, wherein the majority of the acid sites are Lewis acid sites. In addition, the invention relates to a catalyst, catalyst support or precursor, binder, functional binder, coating or sorbent comprising the zirconium hydroxide or zirconium oxide. The invention also relates to a process for preparing zirconium hydroxide, the process comprising the steps of:(a) dissolving a zirconium salt in an aqueous acid, (b) addingone or more complexing agents to the resulting solution or sol, the one or more complexing agents being an organic compound comprising at least one of the following functional groups: an amine, an organosulphate, a sulphonate, a hydroxyl, an ether or a carboxylic acid group, (c) heating the solution or sol formed in step (b), (d) adding a sulphating agent, and (e) adding a base to form a zirconium hydroxide, and (f) optionally adding a dopant.

This invention relates to azirconium hydroxideor zirconium oxide comprising, on an oxide basis, up to 30 wt % of a dopant comprising one or more of silicon, sulphate, phosphate, tungsten, niobium, aluminium, molybdenum, titanium or tin, and having acid sites, wherein the majority of the acid sites are Lewis acid sites. In addition, the invention relates to a catalyst, catalyst support or precursor, binder, functional binder, coating or sorbent comprising the zirconium hydroxide or zirconium oxide. The invention also relates to a process for preparing zirconium hydroxide, the process comprising the steps of:(a) dissolving a zirconium salt in an aqueous acid, (b) addingone or more complexing agents to the resulting solution or sol, the one or more complexing agents being an organic compound comprising at least one of the following functional groups: an amine, an organosulphate, a sulphonate, a hydroxyl, an ether or a carboxylic acid group, (c) heating the solution or sol formed in step (b), (d) adding a sulphating agent, and (e) adding a base to form a zirconium hydroxide, and (f) optionally adding a dopant.

A slurry or slip composed of a dispersion medium and a dispersoid including sinterable raw material powder containing a complex oxide powder represented by the following formula (1):
(Tb.sub.1-x-yR.sub.xSc.sub.y).sub.3(Al.sub.1-zSc.sub.z).sub.5O.sub.12  (1)
wherein R is yttrium and/or lutetium, 0.05≤x<0.45, 0<y<0.1, 0.5<1-x-y<0.95, and 0.004<z<0.2 is prepared; the slurry or slip is subsequently enclosed in a mold container to be subjected to solid-liquid separation by centrifugal casting to mold a cast compact; the cast compact is dried thereafter; a dried compact is degreased; a degreased compact is sintered thereafter; and a sintered body is further subjected to a hot isostatic pressing treatment to obtain the transparent ceramic material composed of the sintered body of garnet-type rare earth complex oxide represented by the formula (1).

Perovskite oxides and catalysts containing the perovskite oxides are provided for the thermochemical conversion of carbon dioxide to carbon monoxide. The perovskite oxides can exhibit large carbon monoxide production rates and/or low carbon monoxide production onset temperatures as compared to existing materials. Reactors are provided containing the perovskite oxides and catalysts, as well as methods of use thereof for the thermochemical conversion of carbon dioxide to carbon monoxide.

Perovskite oxides and catalysts containing the perovskite oxides are provided for the thermochemical conversion of carbon dioxide to carbon monoxide. The perovskite oxides can exhibit large carbon monoxide production rates and/or low carbon monoxide production onset temperatures as compared to existing materials. Reactors are provided containing the perovskite oxides and catalysts, as well as methods of use thereof for the thermochemical conversion of carbon dioxide to carbon monoxide.

The invention relates to a composition containing a catalyst suitable for producing ethylene and other C.sub.2+ hydrocarbons at high selectivity while improving both methane conversion and product yield. Particularly, the catalyst contains mixed metal oxides having at least one alkali earth metal and at least one rare earth metal along with an alkali metal promoter in the form of an alkali metal or in the form of an alkali metal tungstate. The invention further provides a method for preparing such a composition, using a calcination process to calcine the alkali metal promoters together with mixed metal oxides. Additionally, the invention further describes a process for producing C.sub.2+ hydrocarbons, using such a composition.

The invention relates to a composition containing a catalyst suitable for producing ethylene and other C.sub.2+ hydrocarbons at high selectivity while improving both methane conversion and product yield. Particularly, the catalyst contains mixed metal oxides having at least one alkali earth metal and at least one rare earth metal along with an alkali metal promoter in the form of an alkali metal or in the form of an alkali metal tungstate. The invention further provides a method for preparing such a composition, using a calcination process to calcine the alkali metal promoters together with mixed metal oxides. Additionally, the invention further describes a process for producing C.sub.2+ hydrocarbons, using such a composition.