8results about How to "Avoid sintering and agglomeration" patented technology

The invention relates to the technical field of flue gas denitration catalysts, in particular to a high-temperature denitration catalyst and a preparation method thereof.The preparation method comprises the following steps that a titanium source, an aluminum source and an alcohol polymer are added into absolute ethyl alcohol, heating and stirring are conducted, and a mixed solution is obtained; the preparation method comprises the following steps: dropwise adding a mixed solution of absolute ethyl alcohol and distilled water into the mixed solution, hydrolyzing to obtain initial gel, and drying and roasting the initial gel to obtain a nanosheet TiO2-Al2O3 oxide; the preparation method comprises the following steps: dipping a nano flaky TiO2-Al2O3 oxide into a vanadium source and a molybdenum source, and then carrying out drying and roasting treatment, so as to obtain the V2O5-MoO3 / TiO2-Al2O3 high-temperature denitration catalyst. The high-temperature denitration catalyst prepared by the invention has excellent denitration activity and sulfur resistance under the condition of high-temperature and high-sulfur flue gas, and effectively solves the problems of poor denitration activity and sulfur resistance of the existing denitration catalyst under the condition of high temperature.

This invention belongs to the field of catalyst technology, specifically relating to a nickel-based reverse piezoelectric catalyst, its preparation method, and its application. The catalyst uses metallic nickel as both the active component and support, with an oxide loaded on the nickel surface to form the reversed host, and a composite piezoelectric material as the synergistic phase. By total mass, nickel accounts for 50%–95%, the oxide for 1%–50%, and the piezoelectric material for 0.1%–20%. This invention involves mixing and reducing a nickel precursor with an oxide, followed by the composite piezoelectric material to obtain the catalyst. The catalyst utilizes the mechanical force of ball milling and the piezoelectric effect to synergistically catalyze the hydrogenation of carbon dioxide to methane, abandoning traditional high-temperature thermocatalysis. This catalyst can achieve highly efficient carbon dioxide conversion under mild conditions, with 100% methane selectivity and significantly improved reaction efficiency, showing promising application prospects in the field of carbon dioxide resource utilization.

The invention discloses a preparation method of a graphene-coated superfine metal composite material with high thermal stability. The preparation method comprises the following steps: step 1, preparing metal particles coated with organic matters; 2, the metal particles coated with the organic matter are placed in a heating furnace, H2 / Ar mixed gas is introduced, then the temperature in the heating furnace is increased to 700-1000 DEG C, CH4 / Ar mixed gas is introduced into the heating furnace to grow graphene, finally, the temperature in the heating furnace is rapidly reduced, and metal particles coated with graphene are obtained; 3, the metal particles coated with the graphene are pressed into a blocky sample; and 4, the blocky sample obtained in the step 3 is placed in a heating furnace to be subjected to vacuum annealing, and the densified graphene-coated superfine metal composite material is obtained. The method has the advantages of being easy to operate and low in cost, and the prepared graphene-coated superfine metal composite material has the advantage of being good in thermal stability.

This application relates to a silicon nitride magnesium powder, its preparation method, and its applications, belonging to the technical field of structural ceramic powder materials. The preparation method includes: embedding silicon nitride powder into magnesium powder to form a magnesium-based composite powder with a micro / nano composite structure on its surface; mixing the magnesium-based composite powder with a dispersant to obtain a reaction precursor; subjecting the reaction precursor to a self-propagating synthesis reaction to obtain the silicon nitride magnesium composite powder; and sequentially subjecting the silicon nitride magnesium composite powder to acid washing and calcination treatments to obtain the silicon nitride magnesium powder. The prepared silicon nitride magnesium has a yield of over 95%, an oxygen content of less than 0.15 wt.%, and a particle size controlled between 1 μm and 2 μm with uniform distribution; it is suitable for applications such as a sintering aid for high-performance ceramics, a component of refractory materials, and a reinforcing phase in metal matrix composites.

This invention discloses a spherical powder of tantalum-tungsten alloy and its preparation method and additive manufacturing method, belonging to the field of refractory metal material preparation technology. The preparation method includes: subjecting a homogeneous tantalum-tungsten alloy ingot to a three-stage hydrogenation treatment, sequentially holding at 0.01~0.04 MPa and 300~500℃ for 1~3 h, at 0.04~0.08 MPa and 900~1000℃ for 0.5~1 h, and at 0.02~0.05 MPa and 300~400℃ for 0.5~1.5 h. This segmented hydrogenation process controls the diffusion behavior of hydrogen in the alloy, achieving controlled embrittlement and avoiding over-hydrogenation. Further, multi-cycle crushing and dynamic sieving based on the target particle size range are performed to obtain hydride precursor powder, significantly reducing ineffective fine powder and improving the yield and production efficiency of the plasma spheroidization process. The resulting tantalum-tungsten alloy spherical powder has a sphericity of not less than 99%, an oxygen content of not more than 150 ppm, and a concentrated particle size distribution. It is suitable for additive manufacturing processes such as laser selective melting and electron beam selective melting, providing a reliable raw material for the forming of high-performance tantalum-tungsten alloy components.

The invention relates to the technical field of catalyst preparation, and discloses a manganese-based catalyst as well as a preparation method and application thereof. The manganese-based catalyst contains mesoporous epsilon-MnO2, and the specific surface area of the catalyst is 140-200 m < 2 >. G <-1 >; the method comprises a MnCO3 decomposition method and a permanganate titration method, and the MnCO3 decomposition method is used for preparing spherical mesoporous epsilon-MnO2 by controlling the molar ratio of carbonate to manganese salt, the calcination time of MnCO3, the heating rate and other conditions; according to the method, by controlling the interface reaction speed of permanganate and manganese salt, the mesoporous epsilon-MnO2 with the sea urchin-shaped structure is prepared. The manganese-based catalyst prepared by the invention has a relatively large specific surface area and a good empty island structure, and is beneficial to improving the catalytic performance of the catalyst and increasing the temperature required by a catalytic reaction.

The invention relates to an Ag-Pt three-way catalyst with high performance and low cost and a preparation method thereof, and the method comprises the following steps: loading Pt colloid coated with a cerium-zirconium solid solution on an Ag modified molecular sieve, and then spraying on a cordierite carrier to obtain the catalyst. Wherein the cerium-zirconium solid solution coated Pt can effectively avoid sintering agglomeration of noble metal Pt at high temperature, and the high specific surface area of the molecular sieve promotes high dispersion of Ag and exposes more active centers, so that the use amount of the noble metal is reduced, and the performance of the catalyst is improved at the same time; the catalyst prepared by coating the catalyst on the carrier has the excellent characteristics of high performance and low cost, and has a wide market application prospect.

The invention discloses a cerium-zirconium solid solution / manganese-based oxide honeycomb catalyst as well as a preparation method and application thereof, and relates to the technical field of novel materials for environmental catalysis. The catalyst disclosed by the invention is formed by mixing cerium-zirconium solid solution loaded silicate clay and natural manganese ore and then carrying out high-temperature calcination; the mass ratio of the cerium-zirconium solid solution to the silicate clay is (0.5-2): 1, and the molar ratio of zirconium to cerium is (0.15-0.35): 1; and the mass of the manganese-based oxide accounts for 25-77% of the total mass of the catalyst. An alkaline ureido silane coupling agent is grafted to the surface of silicate clay, cerium and zirconium hydroxide precursors are generated on the surface of a silicate clay carrier through in-situ precipitation, then a cerium-zirconium solid solution precursor / silicate clay compound and a manganese ore mixture are subjected to high-temperature calcination forming, and the non-noble metal monolithic honeycomb catalyst is prepared. The honeycomb catalyst prepared by the invention has excellent chlorine poisoning resistance and low-temperature catalytic activity.