2192 results about "Oxygen reduction" patented technology

A method and installation are disclosed which can, for example, provide for reliable, low-Nox-emission operation of a gas turbine installation with hydrogen-rich fuel gas. An exemplary gas turbine installation includes an arrangement for flue gas recirculation into a compressor inlet and for fuel gas dilution. Oxygen content in combustion air can be reduced by recirculation of recooled flue gas, and the fuel gas can be diluted with compressed flue gas. The oxygen reduction in the combustion air can lead to minimum residual oxygen in the flue gas which can be used for fuel gas dilution. As a result of the flue gas recirculation, water content in the combustion air can be increased by feedback of the water which results as a combustion product. The oxygen reduction, increased water content, and fuel dilution can reduce the flame velocity of hydrogen-rich fuel gases and enable a robust, reliable and low-emission combustion.

A bio-implantable electrochemical cell system for active implantable medical devices. In one embodiment, the fuel cell includes an electrode structure consisting of immobilized anode and cathode enzymes deposited on nanostructured high-surface-area metal nanowires or carbon nanotube electrodes. The anode enzyme comprises immobilized glucose oxidase and the cathode enzyme comprises immobilized laccase. Glucose is oxidized at the surface of the anode and oxygen is reduced at the surface of the cathode. The coupled glucose oxidation-oxygen reduction reactions provide a self-generating current source. In another embodiment, the nanowires or carbon nanotubes, along with the adjacent surface anode and cathode electrodes, are coated with immobilized glucose oxidase and immobilized laccase containing biocolloidal substrates, respectively. This results in the precise construction of an enzyme architecture with control at the molecular level, while increasing the reactive surface area and corresponding output power by at least two orders of magnitude.

Air electrodes for secondary metal-air batteries or secondary metal hydride-air batteries, in particular, bifunctional air electrodes that can undergo oxygen reduction and oxygen evolution with high reaction rates. A method of manufacturing such electrodes.

Systems and methods drawn to an electrochemical cell comprising a low temperature ionic liquid comprising positive ions and negative ions and a performance enhancing additive added to the low temperature ionic liquid. The additive dissolves in the ionic liquid to form cations, which are coordinated with one or more negative ions forming ion complexes. The electrochemical cell also includes an air electrode configured to absorb and reduce oxygen. The ion complexes improve oxygen reduction thermodynamics and/or kinetics relative to the ionic liquid without the additive.

The invention discloses a preparation method of a catalyst with a core-shell structure for a low-temperature fuel cell, belonging to the technical field of fuel cells. In the catalyst with the core-shell structure prepared with the preparation method, platinum is taken as a shell, a metal alloy consisting of more than one of metals including ruthenium, platinum, iron, cobalt, nickel, copper, tin, iridium, gold and silver is taken as an inner core, and the shell and the inner core are loaded on a carbon carrier. The preparation method comprises the following preparation steps of: reducing a metal chloride or a metal nitrate with a reducing agent, and forming a core on the carbon carrier with a large specific surface area; stabilizing the core; and precipitating Pt on a core layer with a impregnation reduction method, a high-pressure organic sol method, a microwave method or an electrodeposition process to form the catalyst with the core-shell structure. Due to the adoption of the preparation method, the utilization ratio of noble metal platinum is increased, the cost of an electro-catalyst is reduced effectively, and the methanol oxidizing capability and oxygen reducing activity of the obtained catalyst are increased by 10.8 times and 8.7 times in maximum respectively in comparison to the mass ratio and activity of a commercial JM4100Pt/C catalyst.

The invention relates to platinum-metal oxide composite particles and their use as electrocatalysts in oxygen-reducing cathodes and fuel cells. The invention particularly relates to methods for preventing the oxidation of the platinum electrocatalyst in the cathodes of fuel cells by use of these platinum-metal oxide composite particles. The invention additionally relates to methods for producing electrical energy by supplying such a fuel cell with an oxidant, such as oxygen, and a fuel source, such as hydrogen.

The invention is a fuel cell (20) having a corrosion resistant and protected cathode catalyst layer (24). The cathode catalyst layer (24) includes a platinum oxygen reduction catalyst and an oxygen evolution catalyst selected from the group consisting of catalysts that are more active than platinum for oxygen evolution. The oxygen evolution catalyst may be uniformly applied within the cathode catalyst layer, or non-uniformly applied to identified high corrosion areas (82) (84) of the cathode catalyst layer (24). The cathode catalyst layer (24) may include heat-treated carbon support material, and/or a heat-treated carbon black within a diffusion layer (40) supporting the cathode catalyst layer (24). The fuel cell (20) may also include an anode catalyst layer (22) having a poor oxygen reduction catalyst having a greater oxygen reduction over potential than platinum.

The invention discloses a preparation method of a cobalt electro-catalysis oxygen reduction material wrapping a nitrogen-doped carbon nanotube. The method includes the following steps of making melamine, cobalt nitrate hexahydrate and glucose react to obtain a self-assembled melamine precursor, and baking the self-assembled melamine precursor to obtain a cobalt nanoparticle hybrid material electro-catalysis oxygen reduction agent wrapping the nitrogen-doped carbon nanotube. In preparation of the precursor, a self-assembled body can be formed through the electrostatic interaction and the hydrogen-bond interaction by means of nitrate radicals and melamine under the acid condition, cobalt ions are adsorbed into the self-assembled body, ordered arrangement and assembly of materials in the high-temperature baking process are facilitated by the pre-assembled precursor, and therefore more catalysis active sites are exposed, and the improvement of the performance of a catalyst is facilitated.

The present invention is usable in oxygen electrodes and air electrodes for air cells, fuel cells, electrochemical sensors and like electrochemical devices. The present invention provides a very stable oxygen-reducing electrode that can achieve electrochemical reduction of oxygen at a noble potential.

The oxygen-reducing electrode of the present invention contains a cobalt tetrapyrazinoporphyrazine derivative represented by the following Structural Formula (1) as a catalytic component.

PCT No. PCT/FR96/00495 Sec. 371 Date Oct. 7, 1997 Sec. 102(e) Date Oct. 7, 1997 PCT Filed Apr. 2, 1996 PCT Pub. No. WO96/31638 PCT Pub. Date Oct. 16, 1996Process for depositing a film of a metal oxide or of a metal hydroxide on a substrate in an electrochemical cell, wherein (i) the metal hydroxide is of formula M(OH)xAy, M representing at least one metallic species in an oxidation state i chosen from the elements in Groups II and III of the Periodic Table, A being an anion whose number of charges is n, 0<x</=i and x+ny=i, (ii) the electrochemical cell comprises (a) an electrode comprising the substrate, (b) a counterelectrode, (c) a reference electrode and (d) an electrolyte comprising a conducting solution comprising at least one salt of the metal M, the process comprising the steps of: dissolving oxygen in the electrolyte and imposing a cathode potential of less than the oxygen reduction potential and greater than the potential for deposition of the metal M in the electrolyte in question on the electrochemical cell.

The invention relates to an iron, cobalt and nitrogen codoped carbon catalyst and a preparation method and application thereof. An iron/cobalt double-metal zeolite imidazate framework material is adopted as a precursor, and the iron, cobalt and nitrogen codoped carbon catalyst is prepared and obtained through high-temperature pyrolysis, wherein the iron/cobalt double-metal zeolite imidazate framework material is prepared by adopting ferrous sulfate, cobalt nitrate and 2-methylimidazole to carry out a self-assembly reaction in a solvent under an oxygen-free environment. The iron, cobalt and nitrogen codoped carbon catalyst prepared in the invention has the advantages that the oxygen reduction catalytic activity, electrochemical stability and methanol poisoning resistance is superior to those of commercial Pt/C, the cost is low, the preparation method is simple and volume production can be realized. The catalyst disclosed by the invention can be widely applied to the fields of fuel batteries, metal-air batteries and the like.

The invention relates to the field of catalysts for energy-producing devices such as fuel cells, metal-air cells, electrolysed water and the like, in particular to a dual-function non-noble-metal catalyst and a preparation method thereof. The structure of the dual-function catalyst with activity of realizing oxygen reduction and oxygen release simultaneously is that non-noble-metal nanoparticles are dispersedly coated with a two-dimensional nitrogen-doped porous carbon layer, and the active center of the catalyst is the non-noble-metal nanoparticles coated with nitrogen-carbon, non-noble-metal-nitrogen-carbon and the carbon layer. The non-noble-metal oxygen electrode catalyst has the advantages that raw materials are cheap, a preparation process is simple and template removal and other complicated operating steps are avoided, thereby being suitable for commercial production and capable of substantially reducing cost under the premise that catalytic performance is guaranteed.

The invention discloses application of a nitrogen-doped porous carbon fixed Co@Pt nano-particle composite material, prepared by taking ZIF-67 as a template, as an efficient catalyst for oxygen reduction catalytic reaction of a cathode of a fuel cell. The application has the superiorities that (1) a synthetic method of the catalyst is simple and feasible, the shape of the catalyst is controllable, batch preparation can be realized, and the catalytic performance is very stable; (2) the oxygen reduction catalytic reaction of nitrogen-doped porous carbon fixed cobalt-platinum core-shell nano-particles in the cathode of the fuel cell shows that the nano-particles have good catalytic activity and excellent methanol poisoning resistance stability, and compared with traditional commercial Pt/C, the nano-particles have relatively high take-off potentials and half-wave-peak potentials (nano-particles: 0.99V and 0.87V, and Pt/C: 0.98V and 0.83V); and (3) metal organic frameworks (MOFs) for preparing the catalyst have sequential microcellular structures and relatively large specific surface areas and can be widely applied to the storage and conversion of energy sources. Therefore, a method for simply and directly preparing cheap and efficient cathode oxygen reduction electro-catalyst is provided for the fuel cell and has a wide application prospect.

The invention discloses a method for preparing nitrogen-doped graphene with high nitrogen doping amount. The method comprises the following steps: (1) dispersing of graphene; (2) ultrasonic dispersion; (3) microwave heating; and (4) filtering and drying. The nitrogen doping amount of the nitrogen-doped graphene prepared by the method disclosed by the invention is 10%-15.0%, the density of free carriers in graphene is greatly increased by the high nitrogen doping amount, the interaction of graphene and metal is enhanced, no oxidation pretreatment is carried out, no toxic solvent is used in the reaction process, reactants are simple in component, reaction conditions are mild, and the prepared nitrogen-doped graphene has excellent electrochemical property and can be used for preparation of new energy materials such as lithium ion battery, lithium-air battery, super capacitor electrode material and fuel cell oxygen reduction catalysts. According to the method disclosed by the invention, a high-pressure kettle is heated by using microwaves without high temperature; the method is low in energy consumption, is carried out in an airtight environment and therefore hardly causes environment pollution; in addition, the method is simple in process and convenient to operate and needs less production equipment, thus, the cost is further reduced.

The invention provides a preparation method and an application of a nitrogen and phosphorus co-doped porous carbon catalyst and belongs to the field of oxygen reduction catalysts for a fuel cell cathode. Nitrogen and phosphorus are introduced with an in-situ doping method, and the nitrogen and phosphorus doping amount is changed by adjusting the content of a nitrogen and phosphorus precursor. Besides, nitrogen and phosphorus co-doped porous carbon is prepared with a hard template method, and controllability of pore diameters of the porous carbon is realized by adjusting a hard template. The method comprises steps as follows: an earlier polymer of aniline monomers, a phosphorus precursor, a silica-based hard template and non-precious metal salt is prepared; the earlier polymer is calcined, and solids are obtained; the solids are etched, cleaned and dried, and the carbon material is obtained. More importantly, the prepared nitrogen and phosphorus co-doped porous carbon material has an excellent oxygen reduction electro-catalytic property under the acid condition and has huge application potential.

This invention relates to a method for fabricating solid-state alkaline polymer Zn-air battery, which consists of a zinc-gel anode, an air cathode electrode, and alkaline polymer electrolyte. The formulation of said zinc gel anode is similar to that of alkaline Zn-MnO2 battery. The zinc gel anode contains a mixture of electrolytic dendritic zinc powders, KOH electrolyte, gelling agent and small amount of additives. The air cathode electrode is made by carbon gas diffusion electrode, which comprises two layers, namely gas diffusion layer and active layer. The active layer on the electrolyte side uses a high surface area carbon for oxygen reduction reaction and potassium permanganate and MnO2 as catalysts for oxygen reduction. The diffusion layer on the air side has high PTFE content to prevent KOH electrolyte from weeping or climbing. Due to adequate amount of fresh air and oxygen supply, the air cathode electrode can run continuously. Theoretically, the polymer zinc-air battery is an accumulator if the cell has sufficient zinc powder and electrolyte, and the air cathode plays the role of energy transfer.

The invention relates to a non-metallic bi-functional oxygen catalyst for graphene/nickel iron type hydrotalcite as well as a preparation method and electric catalytic application thereof to oxygen evolution reaction and oxygen reduction reaction in an alkaline medium. The catalyst takes a micelle as a template, and under the hydrothermal and reducing conditions, the nickel iron type hydrotalcite is assembled onto graphene in sequence to form a spherical porous graphene oxide/nickel iron type hydrotalcite compound. The method comprises the following steps: dispersing graphene oxide and metal salt in the micelle, introducing an alkali source, synthesizing the graphene oxide/nickel iron type hydrotalcite compound under the hydrothermal conditions, and performing hydrazine hydrate reduction on an obtained product to obtain the catalyst. The catalyst prepared by the method has high oxygen evolution and oxygen reduction catalytic activity, good stability and excellent methanol tolerance under the alkaline conditions and is low in cost of raw materials used, simple in preparation method, easy to operate and convenient for large-scale production.

The invention relates to a nitrogen-sulfur double-doped carbon material difunctional oxygen catalyst, a preparation method thereof and electrocatalysis application of alkaline medium in oxygen. In the catalyst, ocean polysaccharide sodium alginate is used as a carbon source, thiourea is sources of nitrogen and sulfur atoms, and double doping is performed on N and S which have electronegativity by high-temperature calcination in an inertia atmosphere to obtain a nitrogen-sulfur double-doped carbon material electrocatalyst. Since a double-doped crystal structure of heteroatoms is changed, the specific area and the catalyst site of the catalyst are improved, meanwhile, relatively high oxygen evolution (OER) and oxygen reduction (ORR) catalytic activity are achieved, and the overoptential of OER and ORR is effectively reduced; the ORR process is most divided to four electron catalytic mechanisms and is an relatively ideal ORR reaction process, and the catalyst has favorable stability and excellent methyl alcohol resistance; and the used raw material is low in cost, the preparation method is simple and is easy to operate, and mass production is facilitated.

The invention relates to a non-platinum catalyst, in particular to an oxygen reduction catalyst for a proton exchange membrane fuel cell and preparation and application thereof. The catalyst can be prepared by the following steps of: (1) synthesizing polypyrrole (PPy); and (2) preparing an M/N-C catalyst, wherein the M/N-C catalyst can be taken as a cathode oxygen reduction catalyst for the proton exchange membrane fuel cell.

The invention belongs to the field of carbon materials and electrochemistry, and discloses a heteroatom-doped porous graphite electro-catalyst and preparation and application thereof as well as a device. The method comprises the following steps: firstly adding concentrated HNO3 into a graphite oxide aqueous solution, performing sealing, ultrasonic reaction and stewing, and pouring the solution into deionized water for centrifugation, filtering and drying to obtain graphite oxide with holes in the surface; uniformly mixing the graphite oxide with holes in the surface, a heteroatom-doped source compound and a solvent to obtain a mixture, coating the surface of a substrate with the mixture, and performing freeze drying to obtain a solid thin film; putting the substrate loaded with the solid thin film into a plasma high-temperature tubular reactor for reaction to obtain the heteroatom-doped porous graphite electro-catalyst. The prepared electro-catalyst is higher in oxygen reduction electro-catalytic performance and is higher in electrochemical performance when applied in an electrode material; the electro-catalyst can be applied to the field of proton exchange membrane fuel batteries, direct alcohol fuel batteries and metal-air battery anode materials.

The invention refers to an oxygen reduction electrode comprising at least three layers: a current collector; a diffusion layer comprising at least PTFE; and a catalytical active layer, comprising at least a mixture of perovskites and pyrolysed macrocycles. In this way, oxygen may be utilised from air without an initial removal of carbon dioxide. Moreover, the invention refers to methods for preparing the electrode, as well as fuel cells and other products wherein the electrode can be used.