Abstract: A composition of zirconium oxide and at least one oxide of a rare earth other than cerium is described. The zirconium oxide has a weight proportion of at least 50% and, after calcination at a temperature of 900° C. for 4 hours, the composition exhibits two populations of pores of which their respective diameters are centered. The diameter of the first pore has a value of from 20 nm to 40 nm and in the second pore has a value of from 80 nm to 200 nm. Further described is how the composition can be used for treating the exhaust gases of internal combustion engines.

Abstract: The composition according to the invention is based on zirconium oxide, cerium oxide and at least one oxide of a rare earth other than cerium, in a proportion, by weight, of zirconium oxide of at least 5% and of cerium oxide of at most 90%, and it is characterized in that it additionally comprises silicon oxide in an amount, by weight, of between 0.1% and 2%. This composition may be used in catalysis, in particular in systems for treating the exhaust gases of internal combustion engines.

Abstract: Catalyst compositions include finely divided nanoscale particles of at least one supported oxide selected from among zirconium oxide, titanium oxide or a mixed zirconium/titanium oxide deposited onto an alumina-based or aluminum-oxyhydroxide-based support, wherein, after calcination for 4 hours at 900° C., the at least one support oxide is in the form of nanoscale particles deposited onto the support, the size of said particles being at most 10 nm when the at least one supported oxide is based is zirconium oxide and being at most 15 nm when the at least one supported oxide is titanium oxide or a mixed zirconium/titanium oxide; such catalyst compositions are especially useful for the selective reduction of NOx.

Abstract: Catalyst compositions include finely divided nanoscale particles of at least one supported oxide, based on a zirconium oxide, a titanium oxide or a mixed zirconium/titanium oxide deposited onto a silica based support, wherein, after calcination for 4 hours at 900° C., the supported oxide is in the form of nanoscale particles deposited onto the support, the size of the particles being at most 5 nm when the at least one supported oxide is based on a zirconium oxide, being at most 10 nm when the at least one supported oxide is based on a titanium oxide and being at most 8 nm when the at least one supported oxide is based on a mixed zirconium/titanium oxide; such catalyst compositions are especially useful for the selective reduction of NOx.

Abstract: A composition is described that includes oxides of zirconium, cerium and another rare earth different from cerium, having a cerium oxide content not exceeding 50 wt % and, after calcination at 1000° C. for 6 hours, a maximal reducibility temperature not exceeding 500° C. and a specific surface of at least 45 m2/g. The composition can be prepared according to a method that includes continuously reacting a mixture that includes compounds of zirconium, cerium and another rare earth having a basic compound for a residence time not exceeding 100 milliseconds, wherein the precipitate is heated and contacted with a surfactant before calcination.

Abstract: A composition is described that includes zirconium oxide, cerium oxide and yttrium oxide, or zirconium oxide, cerium oxide and at least two oxides of two rare earths different from cerium in a mass proportion of at least 20% of zirconium oxide and of at most 70% of cerium oxide, wherein the composition further includes, after calcination at 900° C. for 4 hours, two populations of pores having respective diameters centered, for the first population, about a value of 20 nm to 40 nm and, for the second, about a value of 80 nm to 200 nm. The composition can be used for processing exhaust gases of internal combustion engines.

Abstract: A composition is described that includes oxides of zirconium, cerium and another rare earth different from cerium, having a cerium oxide content not exceeding 50 wt % and, after calcination at 1000° C. for 6 hours, a maximal reducibility temperature not exceeding 500° C. and a specific surface of at least 45 m2/g. The composition can be prepared according to a method that includes continuously reacting a mixture that includes compounds of zirconium, cerium and another rare earth having a basic compound for a residence time not exceeding 100 milliseconds, wherein the precipitate is heated and contacted with a surfactant before calcination.

Abstract: A composition including cerium and zirconium oxides, including at least 30 wt.-% cerium oxide is desired. Following calcination at a temperature of 900 DEG C. for 4 hours, the composition has two populations of pores, the diameters of the first population being centered around a value of between 5 nm and 15 nm for a composition including 30% to 65% cerium oxide or between 10 nm and 20 nm for more than 65% cerium oxide and the diameter of the second population being centered around a value of between 45 nm and 65 nm for 30% to 65% cerium oxide or between 60 nm and 100 nm for more than 65% cerium oxide.

Abstract: A porous inorganic composite oxide containing oxides of aluminum and of cerium and/or zirconium, and, optionally, oxides of one or more dopants selected from transition metals, rare earths, and mixtures thereof, and having a specific surface area, in m2/g, after calcining at 1100° C. for 5 hours, of ?0.8235[Al]+11.157 and a total pore volume, in cm3/g, after calcining at 900° C. for 2 hours, of ?0.0097[Al]+0.0647, wherein [Al] is the amount of oxides of aluminum, expressed as pbw Al2O3 per 100 pbw of the composite oxide; a catalyst containing one or more noble metals dispersed on the porous inorganic composite oxide; and a method for making the porous inorganic composite oxide.

Abstract: A composition is described that includes a perovskite of the formula LaMO3, where M is at least one element selected from among iron, aluminium or manganese, in the form of particles dispersed on an alumina or aluminium oxyhydroxide substrate, wherein after calcination at 700° C. for 4 hours, the perovskite is in the form of a pure crystallographic phase, and in that the size of the perovskite particles does not exceed 15 nm. The described composition can be used in the field of catalysis.

Abstract: Catalyst compositions useful for the conversion of vehicular exhaust gases contain zirconium, cerium and yttrium oxides with a cerium oxide proportion of from 3% to 15%, and yttrium oxide proportions corresponding to the following conditions: 6% at most if the cerium oxide proportion is from 12% excluded and 15% included; 10% at most if the cerium oxide proportion is from 7% excluded and 12% included; 30% at most if the cerium oxide proportion is from 3% to 7% included, the balance being zirconium oxide; such compositions may optionally include an oxide of a rare earth selected from among lanthanum, neodymium and praseodymium.

Abstract: Catalyst compositions include finely divided nanoscale particles of at least one supported oxide selected from among zirconium oxide, titanium oxide or a mixed zirconium/titanium oxide deposited onto an alumina-based or aluminum-oxyhydroxide-based support, wherein, after calcination for 4 hours at 900° C., the at least one support oxide is in the form of nanoscale particles deposited onto the support, the size of said particles being at most 10 nm when the at least one supported oxide is based is zirconium oxide and being at most 15 nm when the at least one supported oxide is titanium oxide or a mixed zirconium/titanium oxide; such catalyst compositions are especially useful for the selective reduction of NOx.

Abstract: Catalyst compositions include finely divided nanoscale particles of at least one supported oxide, based on a zirconium oxide, a titanium oxide or a mixed zirconium/titanium oxide deposited onto a silica based support, wherein, after calcination for 4 hours at 900° C., the at least one supported oxide is in the form of nanoscale particles deposited onto the support, the size of the particles being at most 5 nm when the at least one supported oxide is based on a zirconium oxide, being at most 10 nm when the at least one supported oxide is based on a titanium oxide and being at most 8 nm when the at least one supported oxide is based on a mixed zirconium/titanium oxide; such catalyst compositions are especially useful for the selective reduction of NOx.