An electride, which is more stable and can be more easily obtained, is provided or is made available, and as a result, a catalyst particularly useful for chemical synthesis, in which the electride is particularly used, is provided.

A transition metal-supported intermetallic compound having a transition metal supported on an intermetallic compound represented by the following formula (1):

A.sub.5X.sub.3(1)

wherein A represents a rare earth element, and X represents Si or Ge.

Described is a catalyst composition suitable for use as a selective catalytic reduction catalyst, including small-pore molecular sieve particles having a pore structure and a maximum ring size of eight tetrahedral atoms and impregnated with a promoter metal, and metal oxide particles dispersed within the small-pore molecular sieve particles and external to the pore structure of the small-pore molecular sieve particles, wherein the metal oxide particles include one or more oxides of a transition metal or lanthanide of Group 3 or Group 4 of the Periodic Table. A method for preparing the catalyst, a method for selectively reducing nitrogen oxides, and an exhaust gas treatment system are also described.

An extruded honeycomb catalyst for nitrogen oxide reduction according to the selective catalytic reduction (SCR) method in exhaust gases from motor vehicles includes an extruded active carrier in honeycomb form having a first SCR catalytically active component and with a plurality of channels through which the exhaust gas flows during operation, and a washcoat coating having a second SCR catalytically active component being applied to the extruded body, wherein the first SCR catalytically active component and the second SCR catalytically active component are each independently one of: (i) vanadium catalyst with vanadium as catalytically active component; (ii) mixed-oxide catalyst with one or more oxides, in particular those of transition metals or lanthanides as catalytically active component; and (iii) an Fe- or a Cu-zeolite catalyst.

Disclosed are a catalyst, its preparation and use in selective hydrogenation, which catalyst has a porous support grain on which are deposited palladium and silver, and at least one alkali and/or alkaline earth metal; the porous support contains a refractory silica, alumina and/or silica-alumina oxide, where at least 80 wt. % of the palladium is distributed in a crust at the periphery of the support, and at least 80 wt. % of the silver is distributed in a crust at the periphery of the support, the local content of palladium at each point along the diameter of the grain follows the same course as the local content of silver.

The exhaust gas purification catalyst of the present invention includes a ceria particle as a support, and barium supported on the ceria particle, wherein the ceria particle contains lanthanum in its surface part and when the ceria particle is measured by an X-ray photoelectric spectroscopy, the value of the molar ratio of lanthanum atom to cerium atom is 0.029 or more.

Active catalysts for the treatment of a low temperature exhaust gas stream are provided for the direct decomposition removal of NO.sub.x from an exhaust gas stream. The catalyst system may include a mixed oxide composition including cerium oxide and nickel oxide CeO.sub.2NiO. The exhaust gas stream may be provided at a temperature of from about 400 C. to about 650 C. Methods for making the catalyst include co-precipitation techniques, using KOH as a precipitating agent. The catalyst system is configured to catalyze a decomposition of the NOx to generate N.sub.2 without the presence of a reductant. The catalyst may be a cubic structure, with nickel incorporated in a cubic lattice of cerium. The catalyst composition may be represented as Ce.sub.0.5Ni.sub.0.5O.sub.2.

A method for manufacturing metal nanoparticles includes adding at least one metal salt to an ionic liquid to form metal ions in the ionic liquid, and heating the ionic liquid to which the metal salt has been added to thermally reduce the metal ions.

An electrode material which may be used in an electrochemical cell used to convert carbon dioxide into useful products, such as synthetic fuel. The electrode material may comprise nano-sized core-shell catalyst (i.e., core-shell nanoparticles, or CSNs) having a catalytic core component encompassed by one or more outer shells, wherein at least one of the outer shells has a mesoporous structure. Electrochemical cells, electrochemical cell electrodes, and methods of making CSNs are also provided.

Presented is a catalyst composition having exceptional properties for converting sulfur, sulfur compounds, and carbon monoxide contained in gas streams by catalyzed hydrolysis, hydrogenation and water-gas shift reactions. The catalyst comprises underbedded molybdenum and cobalt with an overlayer of molybdenum and cobalt. These metals are present in the catalyst within certain concentration ranges and relative weight ratios. The underbedded metals are present in the catalyst within a specified range relative to the overlayer and total metals. The underbedded metals are formed by co-mulling an inorganic oxide with the catalytically active metals of molybdenum and cobalt. The co-mulled mixture is calcined and then impregnated with overlaid molybdenum and cobalt.

To reduce an OSC material, while maintaining necessary OSC capacity; and to improve heat resistance and reactivity of a precious metal. Proposed is an exhaust gas purifying catalyst which comprises a first catalyst layer that is formed on the surface of a substrate that is formed of a ceramic or a metal, and a second catalyst layer that is formed on the upper side of the first catalyst layer. The first catalyst layer comprises a precious metal, an OSC material and an alumina, and the OSC material and the alumina are comprised at a mass ratio of OSC material:alumina=1:7 to 1:3. The second catalyst layer comprises a precious metal, an OSC material and an alumina, and the OSC material and the alumina are comprised at a mass ratio of OSC material:alumina=1:1 to 10:0.