47results about How to "Increase the limiting current density" patented technology

The invention discloses a sealed electrolysis bath and an electrolytic system, the electrolysis bath comprises two end plates, an anode component, a cathode component, sealing components and a compacting device, wherein liquid flowing ports are evenly arranged on the two end plates, liquid flowing through-holes are correspondingly arranged on the anode component and the cathode component, the anode component and the cathode component are separately arranged between the two end plates, a polar chamber is formed between the anode component and the cathode component, the sealing components are evenly arranged on the contact position of the anode component, the cathode component and the end plates, and the anode component, the cathode component and the end plates form a sealed structure afterbeing compacted through the compacting device. The electrolysis bath has simple structure and can increase the circulation speed of electrolyte, the overpotential is effectively lowered, the current density of an anode and a cathode is increased when in electrolysis, the productivity of unit electrolysis bath is increased, and the electrolysis bath can be widely applied in electrowinning various metal and in electrowinning metallic solution with low concentration. The sealed structure avoids the influence of gas which is discharged in the electrolysis process to environment in a workshop.

The invention discloses a method for preparing tellurium powder. The method comprises the following steps that (1), tellurium dioxide is added to a sodium hydroxide solution, and stirring and then filtering are conducted; (2), the solution filtered in the first step is used as electrolyte and subjected to rotational flow electrodeposition, and after electrodeposition is completed, the electrolyte is filtered, and an electrodeposition product is obtained; and (3), the electrodeposition product obtained in the second step is added to an oxalic acid solution and boiled and washed, and the tellurium powder is obtained after filtering and drying. According to the method, the rotational flow electrodeposition technology is used for the preparation of the tellurium powder for the first time, the flow velocity of the solution is increased with the help of the electrodeposition technology, the tellurium ion concentration of the surface of an electrode is increased, the thickness of a diffusion layer is lowered, the limiting current density is increased, electrodeposition precipitation of tellurium in the solution with the low tellurium content under the high current density is achieved, and the method is a process which is economical and environmentally friendly and is suitable for industrial production.

The invention relates to a high-performance low-platinum cathode catalyst layer structure used for a fuel cell and application thereof. In the high-performance low-platinum cathode catalyst layer structure used for the fuel cell, Pt / C or PtMxOy / C serves as an electro-catalyst; a hydrophilic internal catalyst layer connected with a proton exchange membrane is formed by a Pt / C or PtMxOy / C catalyst (a second catalyst) prepared by a carbon carrier of which the specific area is 800 to 1,200 m<2> / g and a proton conductor serving as main components; and a hydrophobic external catalyst layer connected with a diffusion layer is formed by a Pt / C or PtMxOy / C catalyst (a first catalyst) prepared by a carbon carrier of which the specific area is 50 to 300 m<2> / g or a composite catalyst of the first catalyst and the second catalyst and a water repellent serving as the main components. The low-platinum cathode catalyst layer structure has the characteristics of less Pt dosage, thin thickness, high catalyst utilization rate and limiting current density, high stability and high durability.

The invention discloses a platinum alloy catalyst, its preparation method and its application in a fuel cell cathode catalyst. The method comprises: 1) preparing a mixed solution of the first reducing agent glucose and the precursor of the first metal component platinum; 2. ) under the condition that the pH value of the mixed solution is 3-10, heating and adding a carbon carrier, and raising the temperature to 80-95°C for reaction; 3) adding the precursor of the second metal component, and reacting; 4) cooling and separating the reaction product; 5) Dissolving the reaction product in water, adding a second reducing agent, heating to 80-95°C, and reacting; 6) cooling and separating the reaction product to obtain a catalyst precursor; 7) calcining to obtain a platinum alloy catalyst. The preparation method of the present invention does not require a large amount of organic solvents, and the reaction conditions are mild. In the aqueous solution, non-toxic and mild glucose is used as the main reducing agent, and a second mild reducing agent is introduced to further coordinate dispersion and reduction to prepare a high-efficiency hydrogen fuel cell. catalyst. It has broad application prospects in the field of fuel cell catalysts.

The invention discloses a Co-N-C composite catalyst. The Co-N-C composite catalyst comprises a Co and N codoped carbon nanoparticle and CNTs (Carbon Nanotube), and the Co and N codoped carbon nanoparticle grows on the surface of the CNTs to form a three-dimensional net structure. The Co-N-C composite catalyst takes chitosan as a carbon source and chitosan and urea as nitrogen sources, the CNTs areadded, the Co-N-C / CNTs composite catalyst is synthesized through an in-situ transformation method, the synergistic effect of the Co-N-C and the CNTs obviously strengthens the ORR dynamics of the Co-N-C, the composite catalyst is applied to an aluminum-air battery cathode material, the limiting current density is up to 5.3 mA cm<-2> and is equivalent to that of a commercial Pt / C electrode (5.2 mAcm<-2>); the Co-N-C nanoparticle grows on the surface of the CNTs to form the three-dimensional net structure, so that the composite catalyst is better in electric conduction and has a large specificsurface area, more electrochemical reaction active sites are achieved, the adsorption of molecular oxygen is promoted, the catalysis is further carried out to reduce the molecular oxygen, then the catalytic activity of the ORR (Oxygen Reduction Reaction) is obviously improved; the process method is simple, the cost is low, the requirement on equipment is not high, and the Co-N-C composite catalystis suitable for large-scale production.

A kind of nickel-cobalt binary catalyst that promotes the direct oxidation of sodium borohydride is characterized in that: (1) under normal temperature and pressure, prepare 0.2mol / dm 3 nickel chloride (NiCl 2 ·6H 2 O), 0.0000~0.0300mol / dm 3 Cobalt Chloride (CoCl 2 ·6H 2 O) and 4mol / dm 3 Ammonium chloride (NH 4 The mixed solution of Cl) is an electrodeposition solution; (2) Assembling a two-electrode system: a 1cm×2cm polished Ni sheet is placed in the above solution as a cathode, wherein the working area of ​​the Ni sheet is 1cm×1cm, and a carbon rod (3) Using the constant current method, in a constant temperature water bath at 298.15K, with a deposition current of 2A, and a deposition time of 20s, deposit Ni and Co on the above smooth Ni sheet. The nickel-cobalt catalyst prepared by electrodeposition has a porous structure, and the addition of cobalt makes the catalyst have a larger average pore size and porosity, which significantly increases the specific surface area, increases the number of catalytic active sites, and reduces the resistance to be overcome in the direct oxidation reaction. The charge transfer of the electrode reaction is enhanced; at the same time, the discharge potential of the fuel is reduced, the discharge efficiency of the fuel is significantly improved, and the oxidation performance of the fuel is improved.

The invention relates to a preparation method of an electroplating diamond fret saw, comprising the following technological processes: 1. roughening processing is carried out to micrometer diamond particles in advance, nanometer diamond powder is added in cationic surface active agents according to the proportion of 1 : 3 by mass ratio, so as to prepare uniform and stable nanometer diamond powdersuspending liquid, plating solution is arranged in an electroplating tank, after the weighted nanometer diamond powder suspending liquid is mixed with the micrometer diamond particles according to the proportion of 1 : 3 by mass ratio, and then the mixture is added in the plating solution, the plating solution is circulated continuously, and nickel aminosulfonate is main material in the plating liquid, and boracic acid and nickel chloride are additionally added, and a magnetic stirring device is arranged in the electroplating tank; 2. a steel wire continuously and uniformly passes through theelectroplating tank, under the action of electrical current, nickel ions move to cathode from anode, so as to drive the nanometer diamond powder and the micrometer diamond particles to move to the steel wire, so as to lead the steel wire to be plated with the nanometer diamond powder and the micrometer diamond particles, meanwhile, chemical nickel-plating is carried out to the steel wire; 3. after the steel wire is separated from the electroplating tank, wires are wound up after being cleaned and dried. The method can continuously and quickly produce electroplating diamond fret saw, and the production efficiency is high.