The invention provides a method of producing a metal oxyhydride, capable of synthesizing the metal oxyhydride under reaction conditions close to atmospheric pressure, and excellent in productivity and cost. The method of producing a metal oxyhydride of the present invention includes reacting an oxide with a metal hydride in a hydrogen atmosphere. A non-oxygen element constituting the oxide comprises only one kind of non-oxygen element. A pressure condition of the reaction is 0.1 to 0.9 MPa, and a temperature of the reaction is 500 to 1000° C.

The present disclosure provide for methods of reforming a hydrocarbon such as methane. In an aspect, when the method is driven via renewable energy (e.g., use of solar energy, wind energy, or other renewable energy) and coupled with zero-energy input product gas separation, this enables the capture of pure CO.sub.2 (i.e., carbon sequestration) and carbon-neutral utilization of methane can be achieved. As a result, the present disclosure can provide for a method to reform methane with zero-energy input product gas separation.

The present disclosure provide for methods of reforming a hydrocarbon such as methane. In an aspect, when the method is driven via renewable energy (e.g., use of solar energy, wind energy, or other renewable energy) and coupled with zero-energy input product gas separation, this enables the capture of pure CO.sub.2 (i.e., carbon sequestration) and carbon-neutral utilization of methane can be achieved. As a result, the present disclosure can provide for a method to reform methane with zero-energy input product gas separation.

A mixed oxide catalyst for the oxidative coupling of methane can include a catalyst with the formula A.sub.aB.sub.bC.sub.cD.sub.dO.sub.x, wherein: element A is selected from alkaline earth metals; elements B and C are selected from rare earth metals, and wherein elements B and C are different rare earth metals; the oxide of at least one of A, B, C, and D has basic properties; the oxide of at least one of A, B, C, and D has redox properties; and elements A, B, C, and D are selected to create a synergistic effect whereby the catalytic material provides a methane conversion of greater than or equal to 15% and a C.sub.2.sup.+ selectivity of greater than or equal to 70%. Systems and methods can include contacting the catalyst with methane and oxygen and purifying or collecting C.sub.2.sup.+ products.

A composite oxide including a metal element represented by the composition of general formula:

A.sub.nX.sub.y,

represents an element selected from the group consisting of Sc, Y, and a trivalent lanthanoid; X represents an element selected from the group consisting of Ca, Sr, and Ba; n is 0<n<1; y is 0<y<1; and n+y=1. Also, a metal-supported material in which cobalt particles are supported on the composite oxide.

A composite oxide including a metal element represented by the composition of general formula:

A.sub.nX.sub.y,

represents an element selected from the group consisting of Sc, Y, and a trivalent lanthanoid; X represents an element selected from the group consisting of Ca, Sr, and Ba; n is 0<n<1; y is 0<y<1; and n+y=1. Also, a metal-supported material in which cobalt particles are supported on the composite oxide.

A thermistor sintered body stably provides a desired B constant even if a composition deviation of an additive element has occurred. The thermistor sintered body includes a Y.sub.2O.sub.3 phase and a Y(Cr, Mn)O.sub.3 phase, wherein a chemical composition of Cr, Mn, Ca, and Y excluding oxygen is Cr: 3 to 12 mol %, Mn: 5 to 15 mol %, Ca: 1 to 8 mol %, and Sr: 1 to 25 mol %, with the balance being unavoidable impurities and Y. In the thermistor sintered body, Ca and Sr may be dissolved in the Y(Cr, Mn)O.sub.3 phase.

Provided are: a complex oxide that exhibits high redox ability even at low temperatures, has excellent heat resistance, and stably retains these characteristics even on repeated oxidation and reduction at high temperature; a method for producing the same; and an exhaust gas purification catalyst. The inventive complex oxide contains more than 0 but no more than 20 parts by mass of Si, calculated as SiO.sub.2, per total 100 parts by mass of rare earth metal elements including Ce, calculated as oxides; and has a characteristic such that when it is subjected to temperature-programmed reduction (TPR) measurement in a 10% hydrogen-90% argon atmosphere at from 50° C. to 900° C. with the temperature increasing at a rate of 10° C./min, followed by oxidation treatment at 500° C. for 0.5 hours, and then temperature-programmed reduction measurement is performed again, its calculated reduction rate at and below 400° C. is at least 1.5%.

Provided are: a complex oxide that exhibits high redox ability even at low temperatures, has excellent heat resistance, and stably retains these characteristics even on repeated oxidation and reduction at high temperature; a method for producing the same; and an exhaust gas purification catalyst. The inventive complex oxide contains more than 0 but no more than 20 parts by mass of Si, calculated as SiO.sub.2, per total 100 parts by mass of rare earth metal elements including Ce, calculated as oxides; and has a characteristic such that when it is subjected to temperature-programmed reduction (TPR) measurement in a 10% hydrogen-90% argon atmosphere at from 50° C. to 900° C. with the temperature increasing at a rate of 10° C./min, followed by oxidation treatment at 500° C. for 0.5 hours, and then temperature-programmed reduction measurement is performed again, its calculated reduction rate at and below 400° C. is at least 1.5%.

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.