142results about How to "Improve hydrogen evolution performance" patented technology

The invention discloses a nickel-and-molybdenum based bimetallic carbide loaded on nickel foam and a preparation method and application thereof. Nickel nitrate and ammonium molybdate are adopted as a nickel source and a molybdenum source correspondingly, glucose is adopted as a carbon source, and the bimetallic carbide Mo6Ni6C is grown on the surface of the nickel foam in situ through a hydrothermal and high-temperature carburizing method. The method is easy and convenient to implement, the raw materials are easy to obtain, the preparation cost is low, the reaction period is short, and repeatability is high. The material has the excellent hydrogen evolution performance in the field of electrocatalytic decomposition of water. When the overpotential of hydrogen evolution is -51 mV in an acid electrolyte solution, the electric current density can reach 8-12 mA/cm<2> and is not decreased obviously under the stable work for more than 200 hours; and at the same time, when the overpotential of hydrogen evolution is -34 mV in an alkali electrolyte solution, the electric current density can also reach 8-12 mA/cm<2> and is not decreased obviously under the stable work for more than 300 hours. The nickel-and-molybdenum based bimetallic carbide loaded on the nickel foam not only can be directly used as a working electrode of electrocatalytic hydrogen evolution, but also can be used in the fields of the chlor-alkali industry, the water electrolysis process, solar energy water electrolysis and hydrogen manufacturing and the like.

The invention discloses a preparation method of a Ni3Fe-loaded nitrogen-doped carbon nanometer composite material, and a product and applications thereof. The preparation method comprises following steps: 1, a Ni<2+>/Fe<3+>/PVP mixed sol is prepared; 2, the Ni<2+>/Fe<3+>/PVP mixed sol is subjected to electrostatic spinning so as to obtain solid carbon fiber film; 3, the solid carbon fiber film issubjected to pre-oxidation at air atmosphere at 200 to 300 DEG C, programmed heating is adopted for heat processing at 400 to 1000 DEG C at an inert atmosphere so as to obtain the Ni3Fe-loaded nitrogen-doped carbon nanometer composite material. The preparation method is low in cost, is easy, and is universal; the obtained Ni3Fe-loaded nitrogen-doped carbon nanometer composite material is of a one-dimensional composite structure (carbon nanometer fiber and carbon nanotube); Ni3Fe alloy particles can be embedded into the carbon nanometer fiber and carbon nanotube uniformly; the Ni3Fe-loaded nitrogen-doped carbon nanometer composite material can be taken as a water electrolysis hydrogen evolution electrocatalytic material, and possesses relatively high activity and excellent stability.

The invention provides a preparation method for a Ni(OH)2/Ni/rGO composite hydrogen evolution electrode with a hierarchical structure. The preparation method comprises the following main steps that a foamed nickel base subjected to ultrasound and acidizing treatment serves as an electro-deposition negative electrode firstly, and a Ni/rGO composite hydrogen evolution electrode with a large surface area is prepared through a super-gravity electro-deposition method; then metal Ni particles on the surface of the Ni/rGO electrode react with one of urea, ammonium chloride and ammonium fluoride through a hydrothermal method, the nickel particles serve as a nickel source, and a layer of Ni(OH)2 nanosheets are vertically grown on the surface root position of the nickel particles; and the finally obtained hydrogen evolution electrode has three-stage structures, namely the first-stage structure is foamed nickel base, the second-stage structure is nano nickel particles loaded with graphene sheets, and the third-stage structure is a Ni(OH)2/Ni/rGO composite plating layer of the Ni(OH)2 nanosheets. According to the preparation method for the Ni(OH)2/Ni/rGO composite hydrogen evolution electrode with the hierarchical structure, the prepared composite electrode has the unique hierarchical structure, a large specific surface area and an excellent table hydrogen evolution property.

The invention discloses a preparing method of a 3D-structuer Ni/rGO composite hydrogen evolution electrode. The preparing method mainly comprises the steps that graphite oxide is added into deionized water, and ultrasonic treatment is carried out to obtain graphene oxide dispersion liquid; nickel aminosulfonate, nickel chloride and ammonium chloride are added into the graphene oxide dispersion liquid, ultrasonic treatment is carried out to obtain a composite plating solution, a foam nickel substrate subject to ultrasonic and acidification treatment serves as an electro-deposition cathode, a pure nickel pipe serves as an electro-deposition anode, the strength G of a high gravity field is 350 g, the electro-deposition time ranges from 10 min to 100 min, the electro-deposition temperature is 45 DEG C, the electro-deposition current density is 3 A/dm<2>, and a composite coating obtained through preparing is washed with deionized water to be neutral and is dried; and the prepared Ni/rGO composite electrode has the considerable specific surface area, a uniform and stable coating structure and the excellent hydrogen evolution performance. When the current density is 100.0 mA/cm<2>, the hydrogen evolution reaction overpotential is reduced to 190 mV from 240 mV obtained through conventional electro-deposition preparing.

The invention relates to a tripetaloid tungsten sulfide nano-sphere, a preparation method and an application of the nano-sphere. The preparation method includes the steps: (a) dissolving tungstate and thiourea in water to form mixed solution; (b) placing the mixed solution in a high-pressure autoclave, performing hydrothermal reaction at the temperature of 220-250 DEG C, and centrifuging, washing and drying the mixed solution. The weight ratio of the tungstate to the thiourea is 4.2:(1.3-5.3). The preparation process is simple, needed equipment is conventional, raw materials are rich, the price is low, a petal-shaped tungsten sulfide nano electro-catalyst is synthesized at low cost, the prepared petal-shaped tungsten sulfide catalyst has good electro-catalytic stability, and stable electro-catalytic hydrogen evolution activity is still kept after circulation is performed for 40000 seconds.

The invention relates to the technical field of electrocatalysis water decomposition, in particular to an electrocatalyst based on FeOOH-NiOOH/NF and a preparation method. After being soaked in a nickel-iron mixed solution simply, the nickel foam grows in situ to obtain the FeOOH-NiOOH/NF composite material. The electrocatalyst based on FeOOH-NiOOH/NF has the excellent electro-catalytic water decomposition performance, is long in service life under high current density, and shows an application prospect in the industrial large-scale production of the oxygen and hydrogen.

The invention relates to a method for preparing a Ni/CeO2 composite hydrogen evolution electrode, which is characterized in that 0.1-20g CeO2 particles with particle size being 10nm-5mum are added in a plating liquid for dispersion treatment, the processed metal copper foil substrate is fixed in a cylindraceous reactor as an electrodeposition cathode for performing electrodeposition, a pure nickel pipe positioned at center axis of the cylindraceous reactor is taken as an electrodeposition anode, temperature is 45 DEG C, current density is 3A/dm<2>, the electrodeposition time is 1 hour, the rotating speed of the cylindraceous reactor is adjusted to obtain a high gravity field with different intensity, high gravity field intensity G scope is 95-1000g, and the direction of the high gravity field is perpendicular to cathode surface. According to the invention, bubble disengaging from an electrolyte during an electrodeposition process is effectively promoted, ion migration and mass transfer process are accelerated, composite particle content in a coating is increased, coating crystal grain is refined, so that the catalyzed hydrogen evolution performance of the prepared Ni/CeO2 composite hydrogen evolution electrode is obviously increased.

The invention discloses a nano-tungsten oxide, a one-step vapor phase reduction preparation method of the nano-tungsten oxide and application of the nano-tungsten oxide. The nano-tungsten oxide takes tungsten trioxide as a tungsten source, and the tungsten trioxide is reduced into nano-scale tungsten oxide WO2.9 in stoichiometric ratio by a vapor phase reduction method; the method has the advantages of simpleness and convenience in operation, simple technical equipment, easily-obtained raw materials, lower preparation cost, short reaction cycle and high repeatability; the material is applied to electrocatalysis hydrogen evolution and shows the excellent hydrogen evolution performance; when the hydrogen evolution overpotential is -70mV, the current density is 8 to 12mA/cm<2>; when the overpotential is -94mV, the current density can reach 15 to 25mA/cm<2>. Not only can the nano-tungsten oxide disclosed by the invention be used as a hydrogen evolution catalyst, but also can be used for hydrogen evolution materials in the chlor-alkali industry, a water electrolysis process, water-electrolytic hydrogen production by using solar energy, electrochemical hydrogen production and other systems.

The invention discloses a preparation method of a modified MoS2/CdS-based composite photoelectrode material and application thereof, and belongs to the technical field of photoelectric catalysis. A simple two-step solvothermal method is used for preparing a MoS2/CdS-based composite catalyst doped with a metal source (Cu, Fe, Co, Ni), and the MoS2/CdS-based composite catalyst is prepared into a photoelectrode for a hydrogen prepartion reaction which is carried out by photocatalytic decomposition of water. The prepared MoS2/CdS-based composite photoelectrode doped with the metal source has goodcatalytic activity and hydrogen evolution performance and cycle stability performance in photocatalytic decomposition water evolution hydrogen reaction.

The invention belongs to the technical field of material synthesis, and particularly relates to a preparation method of a NiCoP@graphene aerogel efficient hydrogen evolution composite material and study for the hydrogen evolution property of the NiCoP@graphene aerogel efficient hydrogen evolution composite material. Polysaccharide and graphene are combined together, hydrogel is formed through thechelate effects of the polysaccharide and metal ions of Co and Ni and then is frozen and dried into aerogel, and the aerogel is further phosphorized into the NiCoP@graphene aerogel composite material,and the NiCoP@graphene aerogel composite material is used for efficient hydrogen evolution under the acidic condition. The preparation method has the advantages that environmental friendliness is achieved, the cost is low, a preparation technology is simple and convenient, and a prepared catalyst is easy to produce industrially on a large scale and has excellent electrocatalytic activity and goodhydrogen evolution stability.

The present invention provides a Ru-based hydrogen evolution catalyst, and a preparation method and an application thereof. The preparation method comprises the following steps: 1) heating a polyaniline fiber to 700-1100 DEG C in an inert atmosphere, and maintaining the temperature for 3-5 h to obtain a black product which is a nitrogen-containing carbon fiber; and 2) dispersing the nitrogen-containing carbon fiber obtained in step 1), melamine and ruthenium chloride in an aqueous solution of boric acid to obtain a suspension, drying the suspension, heating the dried product to 500-800 DEG C under the inert atmosphere, and keeping the temperature for 2-4 h to obtain a black powder that is the Ru-based hydrogen evolution catalyst, wherein a mass ratio of the nitrogen-containing carbon fiberto melamine to boric acid to ruthenium chloride is (2-4):(2-6):(2-6):1. B-and-N-doped carbon nanofibers are used to effectively disperse Ru2B3 nanoparticles, and the catalyst has an excellent hydrogen evolution performance in the whole pH range.

The invention discloses a nickel-nitrogen co-doped porous carbon material loaded with cobalt nanoparticles, and a preparation method and application thereof, and relates to a preparation method of a porous carbon material. The invention aims to solve the problems that conventional methods for preparing porous carbon are tedious in operation steps, time-consuming, high in overpotential, high in equipment requirements and harmful to the environment, limit the preparation of the porous carbon material, are not suitable for large-scale production and cannot meet the new application requirements inthe fields of energy, catalysis, biology and the like. The nickel-nitrogen co-doped porous carbon material loaded with cobalt nanoparticles grows on foamed nickel in situ. The preparation method comprises the following steps: 1, pretreating the foamed nickel; 2, growing a cobalt-based zeolite imidazate framework structure material nanosheet array on the foamed nickel in situ; and 3, carrying outcalcining. The c nickel-nitrogen co-doped porous carbon material loaded with cobalt nanoparticles is used as a catalyst for hydrogen production through water electrolysis in the field of energy. The nickel-nitrogen co-doped porous carbon material loaded with cobalt nanoparticles can be obtained by using the method.

The invention belongs to a hydrogen evolution composite material; a polysaccharide and graphene are combined, a hydrogel is formed by using a chelation effect of the polysaccharide and a metal ion, the hydrogel is freeze-dried to form an aerogel, and the aerogel is further phosphorized to form a Ni2P@C/graphene aerogel high-efficiency hydrogen evolution composite material for high-efficiency hydrogen evolution under acidic conditions. The hydrogen evolution composite material has the advantages of being green, environmentally friendly, low in cost, and simple in preparation process, and the prepared catalyst is easy to be industrially produce on a large scale and has excellent electrocatalytic activity and good hydrogen evolution stability. The carbon aerogel formed by carbonization of thepolysaccharide has a developed network structure which greatly increases the specific surface area of a catalyst. The pore structure of the aerogel plays a very good role in the fixation and dispersion of Ni2P nanoparticles. The electron migration rate is greatly improved, and the electrochemical hydrogen evolution performance of the Ni2P can be significantly improved.

The invention relates to a spiral Mo2C catalyst with an ultralow platinum loading capacity, and a preparation method and an application thereof. The preparation method comprises the following steps: S1, preparing a spiral MoO2 precursor by an electrodeposition technology; S2, preparing a spiral Mo2C catalyst by a chemical vapor deposition process; and S3, preparing the spiral Mo2C catalyst with the ultralow platinum loading capacity by an electroplating process. The spiral Mo2C catalyst with the ultralow platinum loading capacity avoids the agglomeration sintering phenomenon due to its spiralmorphology, has a high hydrogen evolution activity, and can directly participate in the electrolysis reaction of water as an integrated electrode. The preparation method of the invention has the advantages of simplicity, easiness in implementation, good repeatability, great reduction of the preparation cost of the hydrogen evolution catalyst, and great practical application values.

The invention discloses an iron-nickel layered double metal hydroxide/foam nickel composite material and a preparation method and application thereof. The preparation method comprises the following steps: 1) performing a solvothermal reaction on an iron source, ammonium fluoride, urea and foam nickel in the presence of a solvent to obtain a reaction product A; and 2) performing a solvothermal reaction on a nickel source, ammonium fluoride, urea and the reaction product A in the presence of a solvent to obtain the iron-nickel layered double metal hydroxide/foam nickel composite material. The iron-nickel layered double metal hydroxide/foam nickel composite material has the characteristics of low over-potential and high stability, and thus the composite material can be applied in an oxygen evolution reaction and a hydrogen evolution reaction. The preparation method has the advantages of simple raw materials and convenient operation.

The invention discloses a method for in-situ circularly promoting a catalytic performance of a NiP amorphous alloy. Expression formula of the NiP amorphous alloy is NiP20-22. The method comprises thefollowing steps: taking 1M KOH as an electrolyte; connecting a NiP amorphous alloy thin strip with a copper wire and then using as a working electrode; taking a graphite electrode as a counter electrode; taking a Hg/HgO/1M KOH electrode as a reference electrode; performing cyclic voltammetry scanning for more than 5000 times within a voltage range from -0.4V to -2V. According to the invention, repeated cyclic voltammetry scanning is performed in the electrolyte, so that the surface roughness of the NiP amorphous alloy thin strip is increased and the hydrogen evolution performance of the NiP amorphous alloy thin strip is promoted; the method is simple; pollution caused by P volatilization is reduced and hydrogen evolution performance of material is effectively promoted.

The invention discloses a low temperature preparation method for hydrogen evolution cathode material and an application thereof. The method comprises the steps of performing surface treatment on an active metal; performing constant temperature treatment on a prepared precursor reaction solution of the cathode active material at a temperature of -20 DEG C-0 DEG C; placing the surface-treated active metal in the precursor reaction solution of the cathode active material; immersion plating the surface-treated active metal at the temperature of -20 DEG C-0 DEG C; taking out the active metal, washing and blow-drying, and thus the dried active metal is used as the hydrogen evolution cathode material. The preparation method reduces preparation cost of the cathode material and improves hydrogen evolution property simultaneously.