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电化学合成技术（Electrochemical synthesis）Refrigeration, cold, cold, extreme cold: reduce the temperature of local space to less than ambient temperature, known as refrigeration. Reduced to 123K is called pu cold, 123k-4.2 K is called deep cold, reduced to 4.2 K, which is called extreme cold.Dynamic pressure, the use of explosion (nuclear explosion, gunpowder, etc.), such as strong discharge produced by shock wave, in an instant effect on objects at high speed, can make the object interior pressure over dozens of GPa, even thousands of GPa, accompanied by a sudden warming. This high pressure is called dynamic high pressure.Static pressure: using the external mechanical loading way, by applying load slow gradually extrusion research object or sample, when its smaller, just inside the object or sample of internal high pressure. The high pressure produced is called static pressure because of the slow loading of the outside world (usually not accompanied by the temperature of the object).Primary pressure measurement: based on the known basic relationship between pressure and other parameters, the corresponding parameters are established to calculate the pressure. Secondary pressure test: the pressure is measured according to the variation of the pressure component.Vacuum, vacuum, vacuum pump: a given space that is lower than the atmospheric pressure. The degree of vacuum close to vacuum is in the system. A device for producing a vacuum is called a vacuum pump.Absolute vacuum gauge, relative vacuum gauge: measuring the vacuum measure, the direct measurement of pressure is called an absolute vacuum gauge; The measurement of the physical quantity relating to the pressure, its pressure scale needs to be calibrated with an absolute vacuum gauge, called a relative vacuum gauge.Illustrate manometry and secondary manometry answer: primary manometry: mercury manometer and free piston meter is according to the relation between p = F/a measurement function in the area of a force F, the two primary stress of pressure p.What are the criteria for dividing a vacuum? Answer: low vacuum, medium vacuum high vacuum, high vacuum, high vacuum, high vacuumThe operating characteristics of the vacuum pump are usually characterized by the following parameters:A limit pressure: the minimum pressure that can be reached at the entrance of the pump after a long period of pumping without gas escaping into the pump.B pumping rate: the volume of gas flowing through the air inlet section of the pump at a certain pressure.C maximum inlet pressure: the pressure of the pump before starting to work.D maximum pressure: the maximum pressure that the pump outlet can withstand without damaging the vacuum pump.E vacuum production rate: the quality of the gas discharged by the pump in a unit time.F compression ratio: the ratio of the outlet pressure of the vacuum pump to its inlet pressure.Chemical vapor deposition method: a technique of producing solid sediments in gas or gas-solid interfaces by gaseous or vapor pressure.Working principle of thermocouple, advantages and disadvantages. A: two different ingredients of conductor (called the thermocouple wire or hot electrode) synthesis loop at both ends, when the junction temperature is not at the same time, in the circuit will generate electromotive force, this kind of phenomenon called the thermoelectric effect, and the electromotive force called thermoelectric potential. Thermocouple is to use the principle of temperature measurement, which directly used for measuring the medium temperature is called the work at the end of the end (also known as measuring side), the other end is called the cold end (also known as compensation); The cold end is connected with the display instrument or supporting instrument, indicating the thermoelectric potential generated by the thermocouple. Advantages: high accuracy of measurement. Because the thermocouple is directly in contact with the measured object, it is not affected by the intermediate medium. The measurement range is wide. The commonly used thermocouple from - 50 ~ + 1600 ℃ are measured. The structure is simple and easy to use. Thermocouples are usually made of two different kinds of wires, and they are not limited by size and opening, and they are very convenient to use.The mechanism of high temperature fixation should be composed of two processes: chemical reaction in phase interface and material transfer in solid phase. The chemical reaction on thephase a, for different response systems, involves different stages,But all these include the following three processes: the contact between the reactants and the surface effect, the chemical reaction and the new phase composition, crystal growth and structural defect correction. When the reaction is active or liquid, the reaction will not be limited to the interface of the direct contact of the material, but may also be carried out along the free surface of the whole reactant particle. B. The reactant is diffused through the product layer. Migration diffusion can be carried out through crystal internal lattice, surface, interface or crystal fissure. Characteristics: 1) the solid opposite should generally include the reaction of matter in the phase interface and the process of material migration.2) it usually takes place at high temperature. 3) the entire solid should be controlled by the slowest speed. 4) the reaction products of solid reaction should be periodic: raw materials, original products, intermediate products, and final products.In chemical transport reaction, how to select and control temperature according to the heat effect of the reaction? A: if the reaction is endothermic reaction, ΔH is positive, then control source area temperature T1, T2 is higher than deposit zone temperature T2 is greater than the T1, namely this kind of reaction is to transport material has a high temperature to low temperature area. Conversely, when the reaction is exothermic reaction, Δ H negative, then control source area temperature is lower than the deposition area, namely the T2 is less than the T1, this kind of reaction is the material to the high transportation by the low temperature area.To prepare solid powders under high temperature and reducing atmosphere conditions, which equipment are needed and how to install them? Answer: equipment: tube furnace, electrolytic hydrogen plant. A thin layer of WO3 is sprinkled into the nickel boat, and the flow of the hydrogen is gradually moving the nickel boat through the tube, then through the high temperature zone into the cooler. This process is divided into two stages, the first stage is to make the WO3 at 720 c, reductive into brown WO2, then will get WO2, mixed with the same amount of WO3 and mixture in 800 ~ 860 c temperature reduction of metal tungsten, in the first stage of the reduction furnace temperature along the pipe heating parts from 520 c heats up to 720 c. In the second stage of the reduction, the furnace temperature increased from 650C to 860C. The quality of WO3 in each nickel boat was 50 ~ 180g because of the size of the furnace usedCommonly used refrigeration methods. Answer: the common method to cooling can be divided into physical methods and chemical methods, one of the commonly used gas adiabatic expansion refrigeration and cases of refrigeration, another half of the semiconductor refrigeration, gas throttling, eddy current cooling, adiabatic deflated refrigeration, thermoelectric refrigeration.The storage and transfer of liquefied gases: the containers of liquefied gases, which are different from the size and purpose of the volume, usually have low temperature containers, liquid gas storage tanks and so on. Small containers consist of a two-layer copper ball, which is divided into liquid nitrogen and gas containers. The liquid gas storage tank is composed ofthe outer shell, adiabatic structure and the mechanical structure of the inner and outer shell. There are many ways to go from a liquid gas plant to a liquid. Such as liquid air removed from a liquid air tank, the available methods of dumping or with a small siphon, is a large amount of liquid air, a small rubber ball pump up available liquid air play.Hard chemical: originally refers to the high temperature solid instead should method, and with the development of the synthesis technology, the concept of hard chemical tend to "chemistry" extreme conditions, such as ultra high temperature, super high, super vacuum, plasma, etcSoft chemistry: a chemical reaction that is achieved under mild conditionsGreen chemistry: green chemistry refers to the use of chemical products only in the manufacture and application of chemical products (preferably renewable) materials, eliminating waste and avoiding the use of toxic and dangerous reagents and solvents. Today's green chemistry is chemical technology that protects the environment.Sol-gel synthesis: an organic metal compound, metal inorganic compound or the mixture of two kinds of the hydrolytic condensation process, gradually gel post-processing accordingly, finally get the new technology of oxide and other compoundsHydrothermal synthesis: in a certain temperat ure (100 ~ 1000 ° C) and pressure (1 ~ 100 mpa) under the condition of using thechemical reaction of synthesis in solutionCoprecipitation synthesis technology of the requirements of a metal ion salt solution of dissolved in the water large b precipitant to metal ion precipitation precipitation c at the same time according to certain stoichiometric ratio sol agglutination of synthetic process of a source material molecules polymerization, condensation, clusters and colloidal particles grew up the formation of sol b with former body polymerization and polycondensation, gradually form a network structure of the gel, in the process, can form a variety of polymer gel structure c aging, polycondensation reaction in the process continues until the form has a solid 3 d mesh structure d gel dry, accompanied by evaporation of water and volatile matter e pyrolysis stage, in the process, the reticular formation of the gel completely collapsed, before bodies decompose organic matter, completely volatile, at the same time, the crystallinity of target productInorganic salt hydrolysis and polymerization of type a hydrolysis: metal ion hydrolysis polymerization b: hydroxyl polymerization, polymerization metal organic molecular oxygen hydrolysis and polymerization of type a polymerization: the aggregation of alkylation, polymerization, bridge oxygen hydroxyl polymerHigh temperature self-propagating synthesis: materials are prepared using the heat energy of raw materials themselvesThe characteristics of the high temperature self-propagating technology energy fully, products with high purity and highyield, product defects and non equilibrium phase in the more concentrated, so as to make the product more flexible, can make certain the stoichiometric ratio of products, intermediate products and the stationary phase interfaceThe characteristics of high temperature and high pressure water are characterized by the increase of vapor pressure and the ion deposition of water. Water density, viscosity, surface tension and dielectric constant decreaseThe properties of other substances in water under high temperature and pressure change a SiO2: it is not soluble in water at normal temperature, and the solubility can reach 0.16% with the increase of temperature. The solubility of SiO2 in NaOH solution can reach 2.4% b NaBr at room temperature, which is 100% dissociated in water, and the dissociation degree decreases at high temperature and high pressure, and the recrystallization occursThe reaction of qian yitai's preparation of diamond with solvent heat is as followsCCl + 4 na - > C + 4 nacl reaction conditions is 700 ° CHigh temperature and high pressure should also convert graphite into diamond. The design of the experimental design for the preparation of diamond was analyzed by using non-hydrolytic Na as solvent. The three-dimensional network structure of diamond is C (sp3 hybridization), two-dimensional plane structure of graphite is C (sp2 hybridization) C in the CCl is sp3 hybridization, so you don't have to graphite, diamond, C toreplace the Cl in CClElectrochemical synthesis: a method of synthesis by electrochemical reaction.Photochemical synthesis: photochemical reactions that are difficult or must be synthesized by chemical reactions with a chemical reaction.Decomposition voltage: the electrolyte begins to decompose the voltage.Overvoltage: the difference between the actual starting voltage and the theoretical decomposition voltage.Plasma: plasma is also called plasma, which is the ionized gas formed by the ionization of the atoms and atoms after the partial electrons are ionized. It is a state of highly ionized matter, a collection of positive and negative ions, electrons and neutral particles.Microwave synthesis technology, the use of microwave strong electric fields, generated in the microwave using thermodynamic method is less than the upper state atoms, molecules and ions, thus can make some on thermodynamics was not able to response to the synthesis technology.When metal deposition is carried out in electrochemical synthesis technology, how does the current density affect the morphology of the metal? Low - crystal growth time sufficient, not to form new nucleation, large, coarse. High - form morenuclei, tiny and even powdery grains. High - the crystals tend to grow in the metal ion concentration and grow into a tree.How does hot plasma come about? How is cold plasma produced? Hot plasma is produced by arc or ion moment. The cold plasma is produced by low intensity arc, microwave heating and glow discharge.The key to the growth of crystal growth in solution? A solution should be sufficiently high to eliminate the micro-crystal b to find the quasi-saturation point c to be strictly sealed in the growth process by the high precision cooling dThe lifting method of the growth crystals in the melt, the moving crucible method and the equipment of the zone melting method,Advantages and disadvantages of various methods? Pulling method advantages in the process of growth, a class to observe the growth condition of crystal directly, that provides a favorable conditions to control the crystal shape b crystal growth on the surface of the melt child accidentally place and do not contact with the crucible, can significantly reduce the stress of the crystal and prevent crucible wall send generating nuclear c can convenient use directional seed crystal and the "neck". Get a different orientation of single crystal, reduce the dislocation density in the crystal, reduce the Mosaic structure, improve the integrity of the crystal d to faster the rate of growth of high quality crystal defects of a general to make container with crucible, lead to melt with varying degrees of pollution when the melt containing volatile matter, bcontrol component is difficult to use c to have certain limitationsMoving crucible advantages due to seal the raw material in the crucible, a reduced can cause leakage and pollution of the hair, to the composition of crystal easy control operation, can grow a large size of crystal, crystal varieties can grow to be also many, and easy to realize programmed growth c because each crucible melt can separate nucleation, so that we can in a crystal furnace into several crucible, at the same time, it may improve the yield and efficiencyShortcoming is not suitable for growth in the make a volume increase of crystal b because the crystals in the whole growth process in direct contact with the crucible, tend to introduce large internal stress in the crystal and more impurity c is difficult to directly observed in the process of crystal growth, growth cycle is long d if using seed crystal growth in the descent method, how to make the seed crystal in high temperature is neither completely fused, and must make it with partial melting to full growth, it is hard to control technical problemsZone melting method (1) the horizontal zone melting method merit a reduced the crucible melt pollution, and reduce the heating rate b zone melting process can be repeated, so as to improve the purity of crystals or make doping uniformity(2) the advantages of floating zone method doesn't need a crucible, melt with itself only contact, pollution can be reduced to a minimum b growth process is easy to observe drawback strict in heating technology and mechanicaltransmission device flame fusion method merit a growth of single crystal don't need crucible, do the high temperature resistance of the crucible, the material is saved, and avoid the pollution problem of crucible b oxyhydrogen flame combustion, the temperature can reach 2800 degrees Celsius, gu grow high melting point of single crystal growth rate and rapid d c can grow larger crystal defects of a flame temperature gradient is bigger, in the growth of single crystal in poor quality b because the heat source is burning gas, temperature control of stable c grow single crystal of the dislocation density is higher, larger internal stress d for volatile or easy to be oxidized materials, should not use this method single crystal growthCrystallization: the process of crystallization of a liquid metal into a solid metal forming a crystal.Phase change: the mutation occurs in a particular condition (or critical value) in the process of change in the external conditions.Partial coagulation: a kind of operation that condenses a mixture of steam to a certain temperature and the higher components of some boiling point in the original steam.Uniform nucleation: in a cold liquid metal, the driving force is obtained by the energy change of the liquid metal itself, which is directly nucleated by the embryos.Nonuniform nucleation: the process of crystallization of the embryo in a cooled liquid metal in the presence of othersubstances on the surface.Supersaturation: the concentration of a substance at a certain temperature, the concentration of the solution at the time of crystallization, and the saturation concentration of the substance at the temperature, or saturation.。
电化学方法与原理英文Electrochemical Methods and PrinciplesElectrochemistry is a fundamental branch of chemistry that deals with the relationship between electrical and chemical phenomena. It encompasses the study of various processes, such as the generation of electricity from chemical reactions, the use of electrical energy to drive chemical transformations, and the behavior of materials in electrochemical systems. Electrochemical methods have a wide range of applications, from energy production and storage to corrosion protection and analytical techniques.One of the core principles of electrochemistry is the understanding of oxidation and reduction reactions, also known as redox reactions. In these reactions, electrons are transferred between chemical species, resulting in changes in their oxidation states. The driving force behind these electron transfers is the difference in the ability of the participating species to attract and release electrons, known as their reduction potential. By harnessing and controlling these redox processes, electrochemists can design and optimize various electrochemical devices and processes.Electrochemical cells are the fundamental building blocks of electrochemical systems. These cells consist of two electrodes, an anode and a cathode, immersed in an electrolyte solution. The anode is where oxidation occurs, and the cathode is where reduction takes place. The electrolyte provides the necessary ionic conduction between the two electrodes, allowing the flow of ions and the completion of the overall electrochemical reaction.One of the most widely recognized applications of electrochemistry is energy conversion and storage. Electrochemical cells, such as batteries and fuel cells, convert the chemical energy stored in fuels or reactants directly into electrical energy. Batteries, for example, use the principle of redox reactions to generate a flow of electrons, which can then be used to power various electronic devices. Fuel cells, on the other hand, generate electricity by combining fuel (such as hydrogen) and an oxidant (such as oxygen) in an electrochemical reaction.In addition to energy applications, electrochemical methods are also used in a variety of analytical techniques. Electroanalytical methods, such as potentiometry, voltammetry, and electrochemical sensors, utilize the principles of electrochemistry to detect and quantify the presence of specific chemical species in a sample. These techniques are widely used in fields like environmental monitoring, healthcare, and chemical analysis.Corrosion is another area where electrochemistry plays a crucial role. Corrosion is an electrochemical process that involves the deterioration of materials, usually metals, due to their interaction with the surrounding environment. Understanding the electrochemical principles underlying corrosion enables the development of effective strategies for corrosion prevention and mitigation, such as the use of protective coatings, cathodic protection, and the selection of corrosion-resistant materials.Electrochemistry also finds applications in the synthesis and processing of materials. Electrochemical techniques, such as electroplating and electrodeposition, are used to deposit thin filmsor coatings of various materials onto a substrate. These processes are employed in the production of electronic components, decorative finishes, and protective coatings.The field of electrochemistry is constantly evolving, with new developments and applications emerging as our understanding of the underlying principles expands. Researchers continue to explore innovative electrochemical technologies, such as energy storage systems, fuel cells, and electrochemical sensors, to address pressing global challenges related to energy, the environment, and healthcare.In conclusion, electrochemical methods and principles arefundamental to a wide range of scientific and technological fields. From energy conversion and storage to analytical techniques and material processing, the principles of electrochemistry underpin numerous important processes that shape our modern society. As we continue to push the boundaries of scientific knowledge, the importance of electrochemistry will only grow, making it a crucial area of study for scientists and engineers alike.。
第一章电化学理论基础1.1 电化学体系的基本单元1.1.1所有电化学体系至少含有浸在电解质溶液中或紧密附于电解质上的两个电极, 而且在许多情况下有必要采用隔膜将两电极分隔开。
1.1.2电极电极（electrode）是与电解质溶液或电解质接触的电子导体或半导体, 为多相体系。
电化学体系借助于电极实现电能的输入或输出, 电极是实施电极反应的场所。
一般电化学体系为三电极体系, 相应的三个电极为工作电极、参比电极和辅助电极。
化学电源一般分为正、负极；而对于电解池, 电极则分为阴、阳极。
现介绍如下。
工作电极（working electrode, 简称WE）: 又称研究电极, 是指所研究的反应在该电极上发生。
一般来讲, 对于工作电极的基础要求是: 所研究的电化学反应不会因电极自身所发生的反应而受到影响, 并且能够在较大的电位区域中进行测试；电极必须不与溶剂或电解液组分发生反应；电极面积不宜太大, 电极表面最好应均一、平滑的, 且能够通过简单的方法进行表面净化等等。
工作电极可以是固体, 也可以是液体, 各式各样的能导电的固体材料均能作电极。
通常根据研究的性质来预先确定电极材料, 但最普通的“惰性”固体电极材料是玻璃、铂、金、银、铅和导电玻璃等。
采用固体电极时, 为了保证实验的重现性, 必须注意建立合适的电极预处理步骤, 以保证氧化还原、表面形貌和不存在吸附杂质的可重现状态。
在液体电极中, 汞和汞齐是最常用的工作电极, 它们都是液体, 都有可重现的均相表面, 制备和保持清洁都较容易, 同时电极上高的氢析出超电势提高了在负电位下的工作窗口, 已被广泛用于电化学分析中。
辅助电极（counter electrode,简称CE）：又称对电极, 该电极和工作电极组成回路, 使工作电极上电流畅通, 以保证所研究的反应在工作电极上发生, 但必须无任何方式限制电池观测的响应。
由于工作电极发生氧化或还原反应时, 辅助电极上可以安排为气体的析出反应或工作电极反应的逆反应, 以使电解液组分不变, 即辅助电极的性能一般不显著影响研究电极上的反应。
