In one aspect, the disclosure relates to an oxygen-deficient mixed metal perovskite having the formula Sr.sub.xA.sub.1-xFe.sub.yB.sub.1-yO.sub.3-δ, wherein A can be Ca, K, Y, Ba, La, Sm, or any combination thereof; wherein B can be Co, Cu, Mn, Mg, Ni, Ti, or any combination thereof; wherein x is from 0 to 1; wherein y is from 0 to 1; and wherein δ is from 0 to 0.7. Also disclosed are redox catalysts comprising the oxygen-deficient mixed metal perovskites and methods for chemical looping air separation, chemical looping CO.sub.2 splitting, and chemical looping alkane conversion using the disclosed catalysts.

Disclosed is a method for preparing a solid material including manganese, the method including the following steps: a. bringing into contact an aqueous effluent including manganese, for example at least 5 mg/L, typically at least 5 to 50 mg/L, and preferably 7 to 25 mg/L of manganese, with an oxidizing agent, manganese, preferably at a temperature between 10° C. and 50° C., and obtaining an oxidized aqueous solution; b. adding a base to the oxidized aqueous solution obtained at the end of step a) until a pH of between 8 and 12, preferably greater than 9, and preferably from 9 to 10.5, and obtaining a solution including a precipitate; c. filtration of the solution obtained at the end of step b); and d. obtaining a solid material including manganese, and especially manganese (IV) and/or Mn (III).

A system and method of pre-purification of a feed gas stream is provided that is particularly suitable for pre-purification of a feed air stream in cryogenic air separation unit. The disclosed pre-purification systems and methods are configured to remove substantially all of the hydrogen, carbon monoxide, water, and carbon dioxide impurities from a feed air stream and is particularly suitable for use in a high purity or ultra-high purity nitrogen plant. The pre-purification systems and methods preferably employ two or more separate layers of hopcalite catalyst with the successive layers of the hopcalite separated by a zeolite adsorbent layer that removes water and carbon dioxide produced in the hopcalite layers.

A method of preparing a calcined hydrogenolysis/hydrogenation catalyst includes mixing a copper-containing material, manganese-containing material, sodium aluminate, and water to obtain an aqueous slurry; contacting the aqueous slurry with a caustic material to form a precipitate in a caustic aqueous slurry; removing the precipitate from the caustic aqueous slurry; and removing residual water from the precipitate to form a dried precipitate; calcining the dried precipitate to form the calcined hydrogenolysis/hydrogenation catalyst exhibiting a Brunauer-Emmett-Teller (“BET”) surface area of about 5 m.sup.2/g to about 75 m.sup.2/g. The calcined hydrogenolysis/hydrogenation catalyst may include a spinel structure crystallite size of about 15 nm or less. The calcined hydrogenolysis/hydrogenation catalyst may include a tenorite crystallite size of about 20 nm to 30 nm.

The invention relates to an oxygen carrier solid, its preparation and its use in a method of combustion of a hydrocarbon feedstock by active mass chemical-looping oxidation-reduction, i.e. chemical-looping combustion (CLC). The solid, which is in the form of particles, comprises an oxidation-reduction active mass composed of metal oxide(s) dispersed in a ceramic matrix comprising at least one oxide with a melting point higher than 1500° C., such as alumina, and has, initially, a specific macroporous texture. The oxygen carrier solid is prepared from an aqueous suspension containing precursor oxide grains for the ceramic matrix that have a specific size, by a spray-drying technique.

A method of turning a catalytic material by altering the charge state of a catalyst support. The catalyst support is intercalated with a metal ion, altering the charge state to alter and/or augment the catalytic activity of the catalyst material.

A method for preparing an active catalyst for high-efficiency denitration is disclosed. The method includes: a catalyst raw material is charged into a denitration reactor, NH.sub.3 and an inert gas are introduced and then heating is performed, and the temperature is held and then natural cooling is performed, thereby obtaining the catalyst. The active catalyst can greatly improve the denitration activity in low temperature range, and can not only improve the denitration efficiency under the condition without SO.sub.2 and H.sub.2O, but also can improve the denitration efficiency under the condition with both SO.sub.2 and H.sub.2O. The service life of the catalyst is prolonged under the premise of not changing the existing catalyst preparation process, and the economic benefit is significant. The denitration efficiency of a powder catalyst can be increased by 25%, and the denitration efficiency of a honeycombed catalyst or a corrugated catalyst can be increased by 20%.

A perovskite-type oxide catalyst for water-splitting reactions is provided. The catalyst, Ca.sub.2-ySr.sub.yFe.sub.1-xCo.sub.1-xMn.sub.2xO.sub.6-δ where y=0.10-1.90 and x=0.05-0.95, has catalytic activity for both hydrogen- and oxygen-evolution reactions. An exemplary catalyst is CaSrFe.sub.0.75Co.sub.0.75Mn.sub.0.5O.sub.6-δ.

Catalyst for oxygen storage capacity applications that include a zinc doped manganese-iron spinel mixed oxide material. The zinc doped manganese-iron spinel mixed oxide material may be synthesized by a co-precipitation method using a precipitation agent such as sodium carbonate and exhibits a high oxygen storage capacity.

The present disclosures and inventions relate to a catalyst and methods for making same, which are useful in Fischer-Tropsch reactions.