2772 results about "Hydrogen evolution" patented technology

A device for generating hydrogen gas is provided. The device (101) comprises a first hydrogen-containing composition (107) that reacts with a second composition to evolve hydrogen gas; a dispenser (105) adapted to apply the first composition to a first porous member (109); and a conduit (111) adapted to supply the second composition to the first porous member. In a preferred embodiment, the first composition is selected from the group consisting of hydrides, borohydrides and boranes, the second composition is water, and the dispenser is spring-loaded and is charged with the first composition. As the first composition reacts with water at the interface to evolve hydrogen gas, the dispenser forces the reaction product across the interface and out of the dispenser, where it will not interfere with the progress of the hydrogen evolution reaction.

A method of formation and charge of a negative polarizable electrode of an electric double layer capacitor. The method can be used for manufacturing of high capacitance capacitors utilizing the energy of the electric double layer. The methods achieve hydrogen evolution on carbonaceous materials using very negative potentials. The methods provide an EDL capacitor, employing an aqueous electrolyte, with improved specific energy. The methods may also ensure the hermeticity of the capacitor. The methods include pretreating the electric double layer capacitor by keeping the negative polarizable electrode at a desired minimum potential prior to use. Desirably, the minimum potential ranges from about -0.25 to about -1.2 V vs. a reference hydrogen electrode.

The invention discloses a molybdenum disulfide (MoS2) nano-sheet film material and its preparation methods. The film material is characterized in that MoS2 nano-sheets vertically and sequentially grow on a conductive substrate, and the diameters and the thicknesses of the MoS2 nano-sheets are 0.05-2mum and 2-30nm respectively. There are two preparation methods of the film material. One preparation method comprises the following steps: a substrate which can be a copper sheet, a silver sheet, a titanium sheet, a tungsten sheet, a molybdenum sheet or carbon is placed in a solution comprising a molybdate and sulfur-containing compounds (comprising thiourea, thioacetamide and L-cysteine); and the sulfur-containing compounds undergo a hydrothermal reaction to grow the compactly-grown and uniformly-sequential MoS2 nano-sheet films on the substrate. Another method comprises the following steps: the molybdenum sheet is directly placed in a solution of the sulfur-containing compounds (comprising thiourea, thioacetamide and L-cysteine); and the sulfur-containing compounds undergo a sulfuration reaction under a hydrothermal condition to form the compact and uniform MoS2 nano-sheet ordered films. The film has a low hydrogen evolution overpotential (-30mv), a small Tafel slope (52mV/dec) and a high electrochemical stability, and is a hydrogen evolution electrode material extremely having an application prospect.

Excessive evolution of hydrogen in electrolytic deposition of metals on a cathode substrate can be controlled by using a pulsed reverse current. Reverse current pulses interposed between the forward current pulses consume at least some of the nascent hydrogen and prevent the local pH at the cathode surface from becoming excessively alkaline. Control of hydroxide ion concentration by pulsed reverse current alleviates problems caused by reaction of metal-bearing-ions with hydroxide ions generated near the cathode by evolution of hydrogen. The method is useful in depositing functional chromium coatings on electrically conductive substrates from plating baths comprising aqueous solutions of trivalent chromium salts. In such a method the current comprises forward pulses having a duty cycle of from about 50% to about 90% and reverse pulses having a duty cycle of from about 5% to about 30%, and a frequency of from about 5 Hz to about 700 Hz.

The invention provides a method for preparing a high-performance molybdenum-based hydrogen evolution electrode by phosphatizing a molybdate precursor and belongs to the fields of water electrolysis and electric catalytic hydrogen evolution in the chlor-alkali industry. The method comprises the steps of pre-processing foamed nickel, growing the molybdate precursor in situ on the surface of a pre-processed foamed nickel base with the hydrothermal synthesis method, and finally placing the prepared precursor and a phosphorus source into a rube furnace together for phosphating of the molybdate precursor so that the high-performance molybdenum-based hydrogen evolution electrode can be prepared. The method is novel, the technology adopted is simple, production cost is low, the requirement for equipment is low, and the method is suitable for industrial production. Furthermore, the electrode is large in specific area, can be combined with the base firmly, has excellent hydrogen evolution activity and stability, and can be widely applied to the fields of water electrolysis and hydrogen evolution in the chlor-alkali industry.

The invention relates to a nitrogen-phosphorus double-doped carbon-coated transition metal diphosphide hydrogen evolution catalyst and a preparation method thereof. The nitrogen-phosphorus double-doped carbon-coated transition metal diphosphide is characterized in that the structural formula is MP2@NPC, a transition metal diphosphide MP2 is used as a core, nitrogen-phosphorus double-doped carbon NPC is used as a shell so that a core-shell structure is formed, the diphosphide has a nano-particle structure, the particle size is less than 50nm and good crystallinity is obtained. The composite catalyst has the electrocatalytic hydrogen evolution activity similar to that of the commercial platinum carbon and catalyst stability better than that of the commercial catalyst. The catalyst has a wide application prospect.

The invention relates to a preparation method of a solar light splitting water hydrogen production catalyst without noble metal as a cocatalyst. Specifically, graphene is used as a cocatalyst to prepare semiconductor nanoparticle-graphene composite photocatalysts, including CdS-graphene composites and TiO2-graphene composites. The hydrogen production efficiency of the photocatalyst with graphene as the cocatalyst is comparable to or even higher than that of the photocatalyst containing the same mass of noble metal Pt under the same hydrogen production conditions. Graphene materials have good electron aggregation and transport functions, which promote the effective separation of electrons and holes, reduce the probability of proton recombination, and increase the photocatalytic efficiency of photocatalysts and the efficiency of photo-splitting water to produce hydrogen; and the preparation method of graphene materials is simple , cheaper than precious metals, and has no pollution to the environment, which is conducive to large-scale preparation and production. The preparation of photocatalysts using graphene as a cocatalyst has opened up a new method for reducing the cost of hydrogen production from solar energy and improving the efficiency of hydrogen production by photolysis of water.

The invention discloses a preparation method for a NiCoP nanowire electro-catalytic electrode. A NiCo salt nanowire is adopted as a phosphorization precursor, hypophosphite is used as a phosphorus source, and the phosphorization process of the NiCo salt nanowire is achieved by controlling the annealing technique in a stored program control tube type annealing furnace. The diameter of the NiCoP nanowire obtained through the method is 140 nanometers, the length of the obtained NiCoP nanowire is about 3.2 micrometers, and the surface of the nanowire is roughly and evenly grown on a 3D netty foamed nickel substrate, so that the specific surface area and the electric conductivity of an electro-catalytic material are effectively improved, and the electro-catalytic hydrogen evolution performance and stability of an electrode material are improved. The electro-catalytic hydrogen production performance of the electrode is tested in 1M of a KOH electrolyte, the overpotential under the electric current density of 10 mA/cm<2> is 109 mV, and the Tafel slope is 88.5 mV/dec, so that the material has the superior electro-catalytic hydrogen production performance compared with common electro-catalytic hydrogen evolution materials. Meanwhile, the preparation technique is simple, the equipment requirement is conventional, reactive materials are abundant, price is low, and the electrode is environmentally friendly.

The invention discloses an electrolyzed-water catalytic material with a nanometer core-shell structure of cobalt sulfide and molybdenum disulfide. The electrolyzed-water catalytic material is composed of a catalytic active material and a carrier, wherein the catalytic active material is a material with the nanometer core-shell structure of cobalt sulfide and molybdenum disulfide; molybdenum disulfide is a shell; cobalt sulfide is a core; and the carrier is ultrafine carbon fiber. The electrolyzed-water catalytic material provided by the invention has high specific surface area and porosity, is favorable for diffusion and gas desorption of electrolyte, has the characteristics of dual functions of hydrogen evolution and oxygen evolution at the same time, and can be directly used as an electrode for electrocatalytic hydrogen preparation without the need of loading onto the electrode.

The invention provides a preparation method of an efficient Ni-Mo-P/Ni hydrogen evolution electrode, which belongs to the field of electro-catalysis hydrogen evolution. The method comprises steps as follows: removing an oxide layer and oil matters from the surface of a nickel sheet by mechanical polishing and ultrasonic washing; then plating the surface of the pre-processed nickel sheet by pulse electrodeposition, doping P into an Ni-Mo coating to form an Ni-Mo-P nano-crystalline coating with excellent hydrogen evolution performance, wherein the Ni-Mo-P nano-crystalline coating is plated uniformly and is located between a crystalline state structure and an amorphous state structure. The method is simple and feasible, the production cost is low; and the Ni-Mo-P/Ni hydrogen evolution electrode prepared by the method is not only applicable to electro-catalysis hydrogen evolution in chlorine alkali industry, but also is widely applicable to various catalytic hydrogen evolution fields such as solar hydrogen production by water electrolysis, and water electrolysis industry and the like.

The invention relates to a graphene-supported layered MoS2 (molybdenum disulfide) nanocomposite and a preparation method thereof, belongs to the technical field of preparation of nano materials, and is used for solving the problem that graphene-supported MoS2 nanoparticles prepared in the prior art are poorer in catalytic performance due to small composite areas between the nanoparticles and graphene. Ammonium molybdate and thiourea are taken as initiators, and layered nano MoS2 can be supported on the surface of graphene oxide under the hydrothermal condition; after roasting treatment, the graphene-supported layered MoS2 has the higher crystallinity, and the photocatalytic efficiency is more than 1.7 times that of commercial nano titanium oxide. The method is simple and easy to operate; MoS2 nanosheets are uniformly distributed on the surface of the graphene and have larger contact areas with the graphene, so that the nanocomposite has the high catalytic performance and is widely applied to fields of electro-catalysis, photo-catalysis, hydrogen evolution catalysis and the like.

The present invention provides molybdenum and tungsten nanostructures, for example, nanosheets and nanoparticles, and methods of making and using same, including using such nanostructures as catlysts for hydrogen evolution reactions.

The invention belongs to the technical field of electrocatalysis and particularly relates to an iron-doped bimetal phosphide electrocatalyst and a preparation method and application thereof. A hydroxide precursor synthesized by a hydrothermal reaction undergoes a phosphating reaction at a low temperature to produce a Ni1CoxFeyP nanosheet array electrocatalyst. The bimetal phosphide has low chargetransfer resistance and a reaction barrier for a hydrogen evolution reaction and has superior performances in the electrocatalytic hydrogen evolution reaction. The catalyst has a low cost. The preparation method is easy to operate and has simple processes. The electrocatalyst has excellent catalytic performances and provides the basic application research for the material in the field of electrocatalysis.

The invention belongs to the technical field of water electrolysis, and particularly relates to a two-step method and device for producing hydrogen through water electrolysis on the basis of a three-electrode system. According to the device, an electrolytic bath comprises a hydrogen evolution catalysis electrode, an oxygen evolution catalysis electrode and a nickel hydroxide electrode. According to the method, water molecules are electrochemically reduced to hydrogen gas on the surface of the hydrogen evolution catalysis electrode, a Ni(OH)2 electrode is electrochemically oxidized to form a NiOOH electrode at the same time, and electrons flow to the hydrogen evolution catalysis electrode from the Ni(OH)2 electrode through an external circuit in the process; the NiOOH electrode is electrochemically reduced to the Ni(OH)2 electrode, hydroxyl ions are electrochemically oxidized to form oxygen gas on the surface of the oxygen evolution catalysis electrode, and the electrons flow to the NiOOH electrode from the oxygen evolution catalysis electrode through the external circuit in the process. According to the device and the method, the hydrogen production step and the oxygen production step which are synchronous in conventional water electrolysis are effectively separated, the high-purity hydrogen gas can be prepared without any diaphragms through the electrolysis device because the hydrogen production step and the oxygen production step are completely separated, and therefore the cost of producing the hydrogen through water electrolysis is lowered further.

The invention relates to a molybdenum disulfide/carbon black composite hydrogen-evolution electrocatalytic material and a preparation method therefor and belongs to the field of electrocatalytic hydrogen evolution. According to the preparation method, firstly, a carbon black oxide with low degree of oxidation is prepared by adopting an improved Hummer method; and then, the molybdenum disulfide/carbon black composite hydrogen-evolution electrocatalytic material is prepared through one-step solvothermal reaction at the temperature of 220 DEG C in a manner of taking sodium molybdate crystals as a molybdenum source, taking sulfourea as a sulfur source and taking dimethylformamide as a solvent. According to the method provided by the invention, the carbon black oxide with low degree of oxidation is simple in preparation process and high in yield; the molybdenum disulfide/carbon black composite hydrogen-evolution electrocatalytic material is prepared by adopting a simple, convenient and mild one-step solvothermal method, the cost is low, the repeatability is high, and large-scale synthesis is facilitated. When the molybdenum disulfide/carbon black composite hydrogen-evolution electrocatalytic material is applied to electrocatalytic hydrogen evolution reaction, excellent catalysis performance is shown, the reduced current density reaches 25.0mA/cm<2> when tested overpotential is 200mV, and the reduced current density reaches 36.2mA/cm<2> when tested overpotential is 226mV; the molybdenum disulfide/carbon black composite hydrogen-evolution electrocatalytic material has good electrocatalytic stability.

The invention relates to a carbon dioxide electrochemical reduction catalyst as well as a preparation method and an application thereof. The carbon dioxide electrochemical reduction catalyst comprises tin dioxide nanoflower, wherein the tin dioxide nanoflower is synthesized through hydrothermal reaction and comprises the synthesis raw materials including 0.1-0.5M of tin dioxide, 1-5M of trisodium citrate mixed solution and 0.1-0.5M of sodium hydroxide. The carbon dioxide electrochemical reduction catalyst is applied to a carbon dioxide electrochemical reduction catalyst gas diffusion electrode. The carbon dioxide electrochemical reduction catalyst has the advantages that the specific surface area of the catalyst is enlarged, the electrochemical reduction catalytic activity of the catalyst for carbon dioxide reduction is improved, the hydrogen evolution reaction is effectively inhibited, and the selectivity of formic acid in a product is improved.

The invention belongs to the technical field of water electrolysis and particularly relates to a three-electrode system double-electrolytic bath two-step water-electrolytic hydrogen producing device and method. The electrolysis device comprises two independent electrolytic baths 1 and 2, a hydrogen evolution catalyzing electrode, an oxygen evolution catalyzing electrode, a nickel hydroxide electrode and an alkaline electrolyte. According to the electrolysis device, the water electrolysis process is divided into two steps of hydrogen production and oxygen production which are respectively and alternately carried out in the two electrolytic baths 1 and 2. The device has the advantages that the steps of hydrogen production and oxygen production which are simultaneously generated in conventional water electrolysis can be effectively separated and respectively completed in different electrolytic baths, so that high-purity hydrogen can be produced under the condition of adopting no diaphragm and the water-electrolytic hydrogen producing cost is further reduced.

The invention provides a carbon dioxide electrochemical-reduction catalyst, and preparation and application thereof. The carbon dioxide electrochemical-reduction catalyst is characterized by comprising cuprous oxide nanowires, wherein the cuprous oxide nanowires are synthesized by hydrothermal reaction from 0.01-0.05M copper acetate and 0.01-0.05M anisidine at a volume ratio of 0.9:0.1 to 0.1:0.9. According to the carbon dioxide electrochemical-reduction catalyst, and the preparation and application thereof, the specific surface area of the catalyst is remarkably enlarged, the electrochemical reduction catalysis activity of the catalyst for the reduction of carbon dioxide is improved, and hydrogen evolution reaction is effectively inhibited.

The invention belongs to the field of electro-catalytic hydrogen evolution, and particularly relates to a preparation method for a MoS2/CC (molybdenum disulfide/carbon cloth) composite hydrogen evolution electro-catalytic material. The preparation method comprises the following steps: washing and drying CC cut into regular shapes, placing the CC in a mixed solution of phosphomolybdic acid and thiourea, performing ultrasonic treatment to completely soak the CC in the mixed solution, then transferring the CC and the mixed solution into a reaction kettle, performing hydrothermal reaction for 24 hours under the condition of 180 DEG C, performing natural cooling to room temperature, and performing washing, centrifugation and drying to obtain an MoS2/CC composite catalyst. Prepared MoS2 grows on the CC, and is uniformly distributed; and compared with MoS2 prepared by a conventional synthesis method, the prepared MoS2 is small in nanometric size, rich in defect and large in interlayer spacing, and the electro-catalytic hydrogen evolution activity is further improved.

The invention provides a self-supporting transition metal-phosphorus alloy catalyst, and a preparation method and an application thereof, and belongs to the field of alkaline electrolytic bath water decomposition. The preparation method of the catalyst comprises the following steps: mixing the salt of a transition metal element with a phosphorus source, and adding a surfactant or an alkaline solution to obtain an electrolyte; and electrodepositing in the electrolyte with a transition metal conductive substrate as a working electrode in order to obtain the self-supporting transition metal-phosphorus alloy catalyst. The invention also provides the self-supporting transition metal-phosphorus alloy catalyst prepared through the preparation method. The self-supporting transition metal-phosphorus alloy catalyst has excellent electrocatalytic hydrogen evolution and oxygen evolution performances in electrolytic baths.

The invention discloses a zinc / polyhalide energy storage cell. An electrode of conductive inert material and an electrolyte solution of zinc chloride solution and zinc bromide solution are used to form a zinc / polyhalide energy storage cell. The zinc / polyhalide energy storage cell employs zinc and polyhalide with small electrochemical equivalent and high hydrogen evolution overpotential are used as active substances of the cell. Anode and cathode electric pair has high potential difference, and the two together decide that the cell technology has high energy density and power density. Compared with a zinc bromine liquid flow cell, a new system energy storage cell has energy density increased by 30%, power density increased by 10%, obviously enhanced removability and reduced cost of the cell system. The anode and the cathode of the cell employ electrolytes with a same element composition to avoid negative influence on cell performance and life caused by crossed contamination of electrolytes; the cell of the invention has advantages of long cycling life, low cost and good mobility and can be widely applied to fields of energy electric power, transportation and information communication, etc.