200results about How to "Improve oxygen storage capacity" patented technology

The invention relates to a method for preparing a high-thermal-stability cerium-based oxygen storage material, which is characterized in that the cerium-based oxygen storage material comprises cerium dioxide, zirconium dioxide, aluminum oxide in a small amount and at least one rare-earth crystal stabilizer selected from lanthanum oxide, praseodymium oxide, yttrium oxide and terbium oxide. The method comprises the following steps in the preparation process: adding a proper amount of surfactant, to obtain a cerium-based composite oxide material having the characteristics of single crystalline phase, high oxygen storage performance and high specific surface area; and ageing the cerium-based composite oxide material at a high temperature (1,050 DEG C) for 5h until the specific surface area thereof is higher than 35m<2>/g and the oxygen storage capacity thereof is higher than 400 mu mol/g. According to the phase results, the cerium-based oxygen storage material has a uniform-phase structure, moreover, a uniform solid solution with a cubic fluorite structure can be prepared from zirconium dioxide, aluminum oxide, stabilizer and cerium dioxide. The preparation process of the oxygen storage material has the characteristics of simple process, lower production cost, easy industrial scale-up, etc.

A cerium-zirconium composite metal oxide having improved durability at high temperature and a stable oxygen storage capacity is provided. The cerium-zirconium composite metal oxide is characterized in that the total mole number of Ce and Zr is at least 85% based on the total mole number of metal in the composite metal oxide, a molar ratio Ce/Zr is within a range from 1/9 to 9/1, and an isoelectric point of the composite metal oxide is more than 3.5. Preferably, the molar ratio Ce/Zr is within a range from 3/7 to 7/3 and the isoelectric point is within a range from 3.8 to 5.0, and the cerium-zirconium composite metal oxide contains a rare earth metal (excluding Ce) in a concentration of less than 15% by mole based on the total mole number of metal in the composite metal oxide. Also the present invention provides a cerium-zirconium composite metal oxide, characterized in that CeO₂ forms a core surrounded by ZrO₂.

The invention discloses a honeycombed catalyst for low-temperature synergic denitrification, dioxin removal and mercury removal and a preparation method thereof. The honeycombed catalyst employs metatitanic acid and sulfated palygorskite as carriers, copper oxides, manganese oxides and vanadium oxides as active ingredients and rare-earth metal oxides as active aids. The honeycombed catalyst hereincan provide synergic denitrification, dioxin removal and mercury removal at the low temperature of 80-300 DEG C; under the action of the honeycombed catalyst, NOx and dioxin are selectively catalytically reduced into N2, HCl, CO2 and CO; the produced HCl is suitable for serving as a mercury removal aid; elemental mercury, CO, hydrocarbons and alkenes are thoroughly oxidized into mercury oxide andCO2; the honeycombed catalyst has denitrification rate of 95% and above and dioxin removal rate and mercury removal rate of 90% and above.

The invention discloses a method for preparing a cerium oxide-zirconium oxide based composite rare-earth oxide. The method comprises the following steps of: (1) heating a zirconium salt solution at room temperature, slowly adding sulfate ions, controlling the temperature rise rate so that the temperature is increased in the range of 90-95 DEG C when the sulfate ions are added completely, and then preserving heat for 20-100 minutes, thereby forming a zirconium basic sulfate composite salt precursor; (2) adding a cerium salt and a rare-earth metal salt to the precursor solution and stirring evenly, thereby obtaining a slurry; (3) settling the slurry by using basic carbonate and/or a basic oxalate solution, thereby obtaining a precipitate; and (4) filtering and washing the precipitate obtained in the step (3), removing purities, and calcining the washed precipitate. The cerium oxide-zirconium oxide based composite rare-earth oxide prepared by the method by controlling raw materials and process conditions has the characteristics of being high in total fine pore volume, high in fresh specific surface area, high in oxygen storage capacity and the like.

The invention aims to disclose a nanometer ceria-zirconium solid solution and a preparation method thereof. The nanometer ceria-zirconia solid solution comprises the following components according to weight percent: 15 to 65% of cerium oxide, 12 to 70% of zirconia and 10 to 30% of compound oxide composed of other tombarthite oxide except for ceria and zirconium. Compared with the conventional products, the nanometer ceria-zirconium solid solution obtains larger pore diameter and pore volume through modification of a structural directing agent and a dispersing agent, has a favorable capability of resisting high temperature and ageing, and has the advantages of high oxygen storage capability and high speed in oxygen storage and discharge, so that the purposes of the invention are achieved.

The invention relates to a preparation method for the cerium-zirconium-aluminum composite oxide solid solution material with mesopore structure. The mesopore Ce1-x-yZrxAlyO2 (x is equal to 0.10-0.45; y is equal to 0.10-0.45) solid solution with high specific surface (200m2/g through 250m2/g) is prepared for one step by adopting the simple surface active agent (CTMACI) method, the hole diameter ranges from 2.5 nm to 3.4 nm, the worm-shaped channel structure with narrow distribution of hole diameter, and the invention can be used for high activity catalyst or catalyst carrier. In the preparation process, the operation is simple, the raw material is easy to be obtained and the invention is suitable for the industrial enlarged production.

The invention discloses a ceria-zirconia composite oxide-loaded perovskite type catalyst with sulfur resistance. The catalyst comprises an active component, a noble metal promoter and a carrier, wherein the active component is perovskite La1-xSrxMnO3 which accounts for 4 to 14wt% of the catalyst, and x is equal to 0-0.5; the noble metal promoter accounts for 0.01 to 1wt% of the catalyst; the carrier is a Ce1-yZryO2 composite oxide which accounts for 85 to 95% of the catalyst, and y is equal to 0.1-0.5. A preparation process comprises two times of loading: firstly, loading perovskite to the Ce1-yZryO2 composite oxide, and then loading the noble metal promoter to the Ce1-yZryO2 composite oxide. The catalyst provided by the invention reaches relatively high catalyst reactivity during a catalytic combustion process of VOCs, and has relatively high anti-sulfur-poisoning property.

The invention discloses a cuprous modified zeolite diesel engine emission pollutant oxidation and purification catalyst. According to the catalyst, a cuprous modified ZSM-5 molecular sieve and La2O3 form a main catalyst, a CeO2-ZrO2 solid solution is taken as a cocatalyst, SiO2, TiO2 and gamma-Al2O3 form a coating base material and 400-mesh cordierite honeycomb ceramic is taken as a catalyst carrier. The preparation technology comprises the steps of preparation and determination of the raw material amount of a load catalyst, preparation of the cuprous modified ZSM-5 molecular sieve and preparation and coating of coating slurry. The catalyst is used for purifying HC, CO and PM pollutants in diesel engine exhaust by being packaged in a diesel engine oxidation catalyst. a noble metal main catalyst in a traditional diesel engine oxidation catalyst is replaced with the catalyst, so that the production cost is significantly reduced, the sulfur resistance and the heat inactivation resistance of the catalyst are improved, and the catalytic activity of the catalyst in low-temperature oxidation reaction is effectively improved.

The invention provides a cerium/aluminum-based composite oxide with high specific surface area and its preparation method. The composite oxide has chemical formula of AlzCexRyO2, wherein R is rare earth element, x (10-50%), y (1-8%) and z (1-x-y) are molar ratios of Al, Ce and R. The composite oxide is used in three-way catalyst for exhaust gas purification of automobile, has large specific surface area, high thermal stability, and strong oxygen storage ability.

The invention specifically relates to a flat-plate type sulfur-resistant low-temperature SCR denitration catalyst and a preparation method thereof, belonging to the fields of environmental protection and environmental catalysis. The method comprises the following steps: with nanometer composite oxide Ce-ZrO2 as a carrier, manganese oxide as an active component and iron oxide and molybdenum oxide as cocatalysts, carrying out equivalent-volume impregnation, drying, roasting and crushing so as to prepare a powdery catalyst; and subjecting the prepared powdery catalyst to acidification by sulfuric acid and then carrying out mixing, rolling coating, fold pressing, shearing, drying and roasting so as to obtain the flat-plate type sulfur-resistant low-temperature SCR denitration catalyst. The prepared catalyst has denitration activity of 85 to 98% in a temperature range of 80 to 150 DEG C and has excellent resistance to sulfur dioxide poisoning.

The invention relates to metal doped modified layered [delta]-MnO2, preparation and applications thereof. According to the present invention, the metal doped modified layered [delta]-MnO2 is preparedby adding a settling agent through a hydrothermal method, wherein the specific surface area is increased by 5 times compared with the undoped layered [delta]-MnO2, and the pore channels are dense, such that the metal doped layered [delta]-MnO2 has high catalytic oxidation activity and high chlorine resistance, and has efficient catalytic degradation performance on refractory volatile organic compounds in organic waste gas; and the preparation method is simple, and has industrial application value.

The invention discloses a catalyst for synthesis of methanol and formaldehyde through selective oxidation of methane. According to the invention, SiO2 modified by Nb and Ce is used as a carrier, and Mo and Sb are used as active components; in terms of the weight of the finished catalyst, Mo accounts for 5 to 11%, Sb accounts for 7 to 20%, Nb accounts for 1 to 3.5%, and Ce accounts for 1 to 3.5%, with the balance being SiO2. A preparation method for the catalyst used for synthesis of methanol and formaldehyde through selective oxidation of methane comprises the following steps: loading Nb and Ce by using an impregnation method so as to prepare SiO2 modified by Nb and Ce; then loading the active components--Sb and Mo; and finally, carrying out molding and screening so as to prepare the finished catalyst. The catalyst can be used for a selective oxidation reaction of methane for preparation of methanol and formaldehyde at a low pressure and has the advantages of a high methane conversion rate, high methanol and formaldehyde selectivity, etc.

[PROBLEMS] To provide an oxygen storage substance which has higher oxygen storage capacity than conventional substances and is inexpensive. [MEANS FOR SOLVING PROBLEMS] The oxygen storage substance is a calcium aluminosilicate (mayenite), i.e., a substance of a crystal structure which is synthesized by hydrothermally treating a mixture of calcium oxide, alumina (sol), and amorphous silica, has a three-dimensional network composed of AlO₄ tetrahedrons and (Al,Si)O₄ tetrahedrons in which part of the aluminum atoms have been replaced with silicon atoms, with vertex oxygen atoms being shared, and has oxide ions (O₂⁻) occluded in microspaces in the structure. Part of the calcium atoms may be replaced with atoms of a transition metal, e.g., copper.

The invention relates to a ternary catalyst for automobile tail gas treatment. The ternary catalyst comprises a honeycomb substrate, and is characterized in that a lower Pd coating is adhered to the honeycomb substrate, a middle Pd coating is adhered to the lower Pd coating, and an upper Rh coating is adhered to the middle Pd coating; the lower Pd coating comprises a Pd-loaded cerium-zirconium solid solution and La2O3-doped aluminum oxide (La2O3-Al2O3); the middle Pd coating comprises Pd-loaded La2O3-Al2O3 and a bonding agent; the upper Rh coating comprises an Rh-loaded cerium-zirconium solid solution and La2O3-Al2O3. Since the middle Pd coating contains no CeO2 ingredient, and Pd is loaded on La2O3-Al2O3, so that the catalytic capability of the ternary catalyst is improved, and the oxygen storage capability of the ternary catalyst is improved; compared with a traditional Pd/Rh dual-coating ternary catalyst, the ternary catalyst provided by the invention has relatively high hydrocarbon compound, carbonic oxide and oxynitride treatment capacity, and especially has relatively high oxynitride conversion capacity.

The invention discloses a method and system for carrying out zero-emission treatment on high-chlorine desulfurization wastewater and promoting flue gas to be subjected to denitration and mercury removal. The method comprises the following steps: firstly, carrying out reverse refluxing concentration on the desulfurization wastewater and part of the flue gas; after pre-treating the wastewater, pumping the wastewater into a cathode chamber of an electrolysis system, so as to obtain alkaline slurry containing high-concentration chlorine ions; refluxing the alkaline slurry into a pre-treatment coagulation precipitation tank; enabling the high-concentration chlorine ions to penetrate though an anion exchange membrane to enter an anode chamber; electrolyzing in the anode chamber to generate chlorine gas and oxygen gas; after mixing the chlorine gas, the oxygen gas, anode electrolyte and air, conveying a mixture into a prepositioned SCO system to participate in oxidization of Hg<0> and part ofNO. According to the method disclosed by the invention, high-chlorine desulfurization wastewater treatment and the denitration and mercury removal of the flue gas are subjected to ectopic coupling, so that the zero-emission aim of the desulfurization wastewater is realized, the problem of Hg<0> pollution also can be solved through simultaneous oxidation and the content of NO2 in the flue gas is improved; denitration reaction of rapid SCR (Selective Catalytic Reduction) is promoted and simultaneous denitration and mercury removal of the flue gas are realized.

The invention relates to a gas generating agent composition. The gas generating agent composition comprises fuel, an oxidizing agent, a rare earth metal organic salt and an azotetrazolate nonmetal salt which are used as raw material components. By adding the rare earth metal organic salt and the azotetrazolate nonmetal salt to the fuel and the oxidizing agent, the decomposition temperature of the fuel is ahead of time, the fuel decomposition is promoted, and the combustion rate and the gas production rate are increased; and lots of gases are generated after reaction of the azotetrazolate nonmetal salt with oxides, thus enhancing the ignitability, increasing the combustion rate and reducing the combustion temperature. The gas generating agent composition is capable of effectively improving the ignitability and reducing the combustion temperature, meanwhile does not generate residues and is high in gas generation efficiency, large in gas production rate and fast in combustion rate.

The invention relates to a Pt-Pd bimetallic catalyst for NO oxidation. The Pt-Pd bimetallic catalyst comprises a carrier, the carrier is coated with a coating loading precious metal Pt and precious metal Pd, the coating comprises a manganese-aluminum composite oxide and a molecular sieve, the weight ratio of manganese to aluminum oxide in the manganese-aluminum composite oxide is 1:9-99, the coating amount of the coating is 80-180 g/L, the coating amount of the precious metal Pt and the precious metal Pd is 0.5-4.5 g/L, and the weight ratio of the precious metal Pt and the precious metal Pd is (15-1):1. According to a preparation method of the Pt-Pd bimetallic catalyst, firstly, the manganese-aluminum composite oxide is prepared in an equivalent-volume impregnation and high-temperature activation manner; secondly, slurry is prepared, and the precious metal Pt and the precious metal Pd are added; finally, the carrier is soaked into the slurry, dried and sintered to prepare into the catalyst. The preparation method of the catalyst is simple and easy to operate, the prepared catalyst has remarkable oxidizing capacity for NO in tail gas of a diesel vehicle, the conversion ratio of produced NO2 is high, a conversion temperature window of the NO2 is wide, the heat stability of the catalyst is good, and the catalyst has high HC and CO oxidizing capacity.

The invention discloses a Cuo/CexZr1-xO2-M high temperature water gas conversion catalyst in IGCC system, and a preparation method thereof and belongs to the technical field of water gas conversion catalysts. For the catalyst provided by the invention, the copper oxide is used as the active component, the zirconium oxide-cerium oxide composite oxide is used as the carrier, and different types of auxiliaries are also added. The catalyst is characterized in that the content of the active component copper oxide, counted by metal elements, is 10-40wt%; the mass ratio of the cerium oxide to the zirconium oxide is (1:4)-(4:1), the auxiliaries include rare earth elements, such as Y and La, and transition metals, such as Fe, Co and Ni; and the auxiliaries content M is 1-4wt%. The preparation method of the catalyst is a reverse adding coprecipitation method, and such method can be used for improving the specific area and metal dispersity of the catalyst. The Cuo/CexZr1-xO2-M high temperature water gas conversion catalyst has better high-temperature catalytic activity and thermostability, in a 400-500 DEG C reaction temperature region, the Co conversion rate approaches to the balanced conversion rate, and the defect of poor thermostability of the copper-based catalyst is solved. Moreover, the preparation process is relatively simple, so that the catalyst has high practical utilization value.

The invention discloses a preparation method for a low-temperature V-W-TiO2 based selective reduction catalyst. The method comprises the following steps of weighing ammonium metatungstate, ammonium metavanadate, cerous nitrate, oxalic acid powder, zirconium acetate and de-ionized water; performing kneading, drying, grinding and roasting to obtain V-Ce-Zr-W-TiO2 powder; mixing the V-Ce-Zr-W-TiO2 powder, silica sol and the de-ionized water; performing ball-milling, dipping and drying; and finally performing roasting to obtain the catalyst. According to the method, the addition of the cerous nitrate facilitates the dispersion of WO3 and improves the oxygen storage capacity of the catalyst; the addition of the zirconium acetate improves the effect of CeO2; and the synergistic effect of CeO2-ZrO2 and WO3 can facilitate the dispersity of V2O5 on the surface of TiO2, so that the prepared V-W-TiO2 based selective reduction catalyst has the advantages that the low-temperature activity is good, the initiation temperature is lower than 190 DEG C, and the like, and is especially suitable for purification of NOx in diesel exhaust gas.

The invention relates to an oxygen storage material for the catalytic purification of automobile exhaust and a preparation method of the oxygen storage material. The oxygen storage material has a structure formula of CexZr(0.93-x)FeyLa(0.07-y)O2, wherein x is equal to 0.2-0.8 and y is equal to 0-0.01. The preparation method comprises the steps of weighing cerium salt, zircon salt, lanthanum salt and ferric salt according to the stoichiometric proportion in the structure formula and adding the salts in deionized water to prepare mixed solution; adding polyethylene glycol with a molecular weight of 2000-6000 into the mixed solution and adding a precipitator under stirring condition for reaction; after the reaction, carrying out ageing and filtration; and carrying out washing, drying and roasting on filtered matters. The oxygen storage material provided by the invention has good oxygen storage property, after being aged at a high temperature of 1000 DEG C for 5h, the oxygen storage material still has higher oxygen storage property, so that the oxygen storage material has high-temperature ageing resistance which is better than that of cerium-zircon composite oxide oxygen storage materials; and the oxygen storage material is simple in preparation method, easy to operate and suitable for industrial production.