44results about How to "Core-shell structure" patented technology

The invention relates to a method for massively preparing a platinum-based dealloyed electrocatalyst for a cathode of a fuel cell, and belongs to the technical field of electrochemistry and new energy. According to the method, dealloying treatment is carried out by acid vapor; direct contact of a catalyst solid and an acid liquid is avoided; and solid-liquid separation operation is omitted. The dealloyed electrocatalyst prepared by the method has a core-shell structure, improves the utilization rate and the specific activity of noble metal platinum are improved and improves the stability. The preparation method reduces the acid consumption and washing water, and reduces platinum loss in the dealloying process. In addition, use of stirring equipment is also avoided in the preparation process; and the energy consumption is reduced. The preparation method provided by the invention is suitable for massive production of the low-platinum electrocatalyst; the problem of massive preparation of the low-platinum electrocatalyst can be effectively solved; and application of the low-platinum electrocatalyst in the fuel cell is promoted, so that the commercialization process of the fuel cell is promoted.

The invention discloses a method for directly preparing alumina coated ferrite through a high-pressure ultrasonic spray pyrolysis method. A solid-liquid mixture composed of water-soluble aluminum saltand ferrite powder subjected to surface activation is taken as spray precursor solution, the solid-liquid mixture is prepared to be atomized through high-pressure ultrasonic spray, and composite ferrite powder coated with an alumina insulating layer on the surface is formed in a set tube furnace through the pyrolysis method. The method provided by the invention is simple to operate, has low costof raw materials and relatively less steps and needs short reaction time; the coated ferrite powder has excellent dispersity and cannot aggregate; the alumina coating layer formed on the surface is thin and compact, and coating is complete.

The invention discloses a method for preparing magnetic metal-metal core-shell nano particles, which relates to metal nano particles. The method comprises: dissolving chloroauric acid and triphenylphosphine in ethanol respectively, filtering, cleaning, drying, obtaining an organic compound formed by gold and triphenylphosphine, mixing the organic compound with alkylamine, obtaining solution A, mixing an organic solvent A with a noble metal salt, adding mixed solution A, rising the temperature to perform a reaction, cooling and obtaining magnetic metal nano particles; dissolving the obtained organic compound formed by gold and triphenylphosphine in an organic solvent B, injecting obtained magnetic metal nano particles, keeping the temperature between 120 and 160 DEG C for 20 minutes to 1 hour, reducing to obtain gold and wrapping gold on the formed magnetic metal nano particles and obtaining nano particles in which gold and magnetic metal are in a core-shell structure; and washing the nano particles in which gold and magnetic metal are in a core-shell structure, performing centrifugal separation, drying and obtaining powder product, namely magnetic metal-gold core-shell nano particles.

The invention discloses a nickel-zinc ferrite / polyacrylic acid nano-composite material and a preparation method thereof. The nano-composite material is in a core-shell structure and comprises core nickel-zinc ferrite and shell polyacrylic acid; the shell polyacrylic acid coats the nickel-zinc ferrite; and the nano-composite material is represented by Ni0.1-1Zn0.1-1Fe1-3O2-6 / PAA. The preparation method of the nano-composite material mainly comprises the following steps: (1) weighing zinc sulfate, ferrous sulfate and nickel sulfate to prepare a metal salt solution, adding the metal salt solution into an ammonium oxalate solution; (2) adjusting the pH of the mixed solution, and separating and drying the mixed solution to obtain a ferrite precursor; (3) burning the ferrite precursor to obtain the nickel-zinc ferrite; and (4) mixing and reacting the nickel-zinc ferrite and acrylic acid, and separating and drying the mixture to obtain the nickel-zinc ferrite / polyacrylic acid nano-composite material. The nickel-zinc ferrite / polyacrylic acid nano-composite material has the advantages of low specific saturated magnetic field intensity, relatively low coercive force and relatively high soft magnetic property; and the preparation method disclosed by the invention is simple, feasible and low in cost.

The invention discloses a nanosilicon dioxide pellet. The nanosilicon dioxide pellet comprises a silicon dioxide shell body and a polymer nuclear body which is wrapped inside the silicon dioxide shell body. The grain size of the silicon dioxide shell body is 50-1000 nm and the shell thickness of the silicon dioxide shell body is 5-75 nm. The nanosilicon dioxide pellet has a uniform size distribution, a controllable pellet size, shell thickness and cavity rate and good biocompatibility; in addition, the nanosilicon dioxide pellet has good heat stability, a high mechanical property and very good water dispersibility. The invention also discloses a preparing method of the nanosilicon dioxide pellet. The preparing method is a soap-free emulsion polymerization method and is simple to operate; a nano composite pellet with a nuclear shell structure can be synthesized in a large scale, that is, the polymer nuclear body and the silicon dioxide shell body can be formed at the same time; meanwhile, the preparing process is simple and efficient, and the product yield and the product purity are high, and thus the cost is reduced sharply.

The invention discloses a Fe 3 O 4 @Hemoglobin core-shell structure material and preparation method, the core of the material is nano-Fe 3 O 4 Microbeads with hemoglobin shell, Fe 3 O 4 The @hemoglobin core-shell structure material can be used as an electrocatalytic material for water splitting to produce oxygen, while suppressing the generation of hydrogen peroxide in the system. The preparation method is simple and feasible, and does not require special equipment and harsh conditions.