Chapter 2_Physical chemistry of__ solid surface
华中师范大学化学专业英语课件7
厦门大学固体表面物理化学国家重点实验室
• Carbon can form straight chains, -C-C-C-C-C-C-C-C-C-C-
as well as branched chains and ring structures. • In addition carbon atoms can form double and triple bonds with other carbon atoms or with nonmetals, C=C CC C=O CN • The nonmetallic elements that appear most often in organic compounds are O,N,S,P, the halogens(卤素) and H, an element which is present in almost all organic compounds. • The hydrocarbons are organic compounds consisting of only two elements, C and H.
• In the electron dot structure for methane, nd must form four single bonds with the four H atoms.
H H CH
H
State Key Laboratory for Physical Chemistry of Solid Surfaces
• Because of the structural isomerism the molecular formula is not the best way to represent an organic compound. Structural formulas which indicate how the atoms are connected to each other are necessary.
Chapter 2 Propertities of Fluids
dy
Newtonian fluid
Fluid Mechanics
Raymond Ding ©
Fluid Mechanics
Raymond Ding ©
4 Viscosity
The viscosity of a fluid is a measureof its resistance to shear or angular deformation, and it is an inherent property of the fluid.
real fluid 0 ideal fluid 0
etc
K
du dy
m
du
dy
du
O
dy
types of fluid
Fluid Mechanics
Raymond Ding ©
5 Surface Tension of Liquids
Liquids have cohesion and adhesion, both of which are forms of molecular attraction. Cohesion enables a liquid to resist tensile stress, while adhesion enables it to adhere to another body.
modulus of compression
Fluid Mechanics
Raymond Ding ©
2 Compressibility and Expandability of Liquids
V
1 V
dV dT
Physical Chemistry of Solid State Electrolytes
Physical Chemistry of Solid StateElectrolytesSolid-state electrolytes (SSEs) have been studied extensively in recent years due to their potential to revolutionize energy storage technologies by enabling solid-state batteries with higher energy densities, longer cycle lives, and improved safety. Physical chemistry is an essential aspect of SSEs in understanding their fundamental properties and developing new materials with enhanced performances.Crystal Structures of SSEsThe crystal structure of SSEs is crucial for their ionic conduction properties. Most SSEs are composed of metal cations or non-metal anions arranged in a crystal lattice that forms a periodic network of voids or channels. The ionic conductivity of SSEs primarily depends on the accessibility of these channels for the movement of ions.For example, the lithium ion conductor Li10GeP2S12 (LGPS) features a tetragonal crystal structure composed of a three-dimensional network of corner-shared GeS4 tetrahedra. The large 12-coordinate Li+ ions occupy the large voids (12-fold coordination sites) between these tetrahedra, while the small 4-fold coordinated P5+ and S2- ions occupy the smaller voids (4-fold coordination sites), forming a disordered distribution pattern in the channels. This unique structure results in high lithium ion conductivity along the three crystallographic directions, achieving values up to 10^-3 S cm^-1 at room temperature.Defect Chemistry of SSEsThe presence of structural defects in SSEs can lead to enhanced ionic conductivity and electrochemical properties. Point defects (vacancies, interstitials) and line defects (dislocations, grain boundaries) can provide additional sites for charge carriers to move more easily through the material. These defects also affect the chemical stability andmechanical strength of SSEs, thus balancing the trade-off between ion conductivity and the electrolyte's structural integrity.For instance, the Li-ion conductor Li7La3Zr2O12 (LLZO) adopts a cubic garnet structure composed of alternating metal oxide layers and Li+ conducting channels. The presence of lithium and oxygen vacancies in the garnet structure can promote Li+ hopping between adjacent octahedral coordination sites, which is the rate-determining step of ionic conduction in LLZO. The introduction of excess lithium ions via Li2CO3 doping can further increase the ionic conductivity of LLZO by creating new lithium vacancies as well as enhancing the lithium-ion diffusivity.Interface Chemistry of SSEsThe interfacial behavior between the SSE and active electrode materials significantly impacts the battery's performance and stability. Understanding the interface chemistry can help design new SSE-electrode material combinations with enhanced electrochemical performance.For example, the Li-ion cathodes used in lithium-ion batteries usually feature a layered oxide structure, such as LiCoO2, which undergoes structural changes (e.g., structural phase transitions, oxygen loss) during cycling that can result in capacity fading and safety issues. The use of SSEs, such as LiPON (Li3.3PO3.8N0.2) or LLZO, as the electrolyte can suppress the side reactions and prevent the degradation of the electrode material. LiPON forms a thin, uniform, and dense interfacial layer between the cathode and electrolyte that blocks the diffusion of active species and protects the cathode from environmental degradation. LLZO, on the other hand, provides a greater degree of mechanical stability and electrochemical reliability due to its high chemical stability and compatibility with most electrodes.ConclusionThe physical chemistry of SSEs plays a critical role in determining their electrochemical properties and their interactions with other materials in energy storage devices such as batteries and supercapacitors. SSEs need to balance their ionicconductivity with thermal stability, mechanical integrity, and chemical compatibility to enable the development of solid-state batteries with better performance. Further studies on SSEs, including their crystal structures, defect chemistry, and interface chemistry, are necessary to improve the energy density, cycle life, and safety of SSE-based energy storage devices.。
Prentice Hall Biology Chapter 2 《The Chemistry of Life》Summary
The atom is the basic unit of matter. The particles that make up atoms are protons, neutrons, and electrons.•Protons and neutrons form the nucleus,or center of the atom. Protons are positively (ϩ) charged. Neutrons have no charge. Protons and neutrons have about the same mass. •Electrons are negatively (Ϫ) charged particles.Atoms have equal numbers of electrons and protons. For this reason, atoms do not have a charge.A chemical element is a pure substance made up of only one type of atom. An element’s atomic number is the number of pro-tons in one atom of an element. Atoms of the same element can have different numbers of neutrons. These are called isotopes.All the isotopes of an element have the same number of protons and electrons. Because they have the same number of electrons, all isotopes of an element have the same chemical properties.A chemical compound is a substance formed by the joining of two or more elements in definite proportions. Chemical bonds hold the atoms in compounds together. The main types of chemical bonds are ionic bonds and covalent bonds.•An ionic bond forms when one or more electrons are transferred from one atom to another. •A covalent bond forms when electrons are shared between atoms.Atoms joined together by covalent bonds form molecules. A molecule is the smallest unit of most compounds.2–2 Properties of WaterWater molecules (H 2O) are neutral. Yet, the oxygen end of a water molecule has a slight positive charge. The hydrogen end has a slight negative charge. A molecule in which there is an uneven distribution of charges between atoms is called a polar molecule.A water molecule is polar. Polar molecules can attract one another. A hydrogen bond forms from the attraction between the hydrogen atom on one water molecule and the oxygen atom on another. Cohesion is an attraction between molecules of the same substance. Adhesion is an attraction between molecules of different substances.Summary2–1 The Nature of MatterA mixture is formed by two or more elements or compounds that are physically mixed together but not chemically joined. Salt and pepper stirred together are a mixture. Two types of mixtures that can be made with water are solutions and suspensions.•In a solution,all the components are evenly spread out. The substance dissolved in a solution is the solute.The substance in which the solute dissolves is the solvent.For example,in a salt-water solution, the salt is the solute and the wateris the solvent.•Mixtures of water and undissolved materials are suspensions.For example, if you mix sand and water, the water willbecome cloudy. However, once you stop mixing, the sandparticles will filter out and settle to the bottom. This is anexample of a suspension.A water molecule (H2O) can form a hydrogen ion (Hϩ) and ahydroxide ion (OHϪ). Chemists often measure the concentration of hydrogen ions. The pH scale indicates the concentration ofHϩions in a solution. The pH scale ranges from 0 to 14.•Pure water has a pH of 7.•An acid forms Hϩions in solution. Acidic solutions havehigher concentrations of Hϩions than pure water. Theyhave pH values below 7.•A base forms OHϪions in solution. Basic, or alkaline, solu-tions have lower concentrations of Hϩions than pure water.They have pH values above 7.2–3 Carbon CompoundsOrganic chemistry is the study of compounds with bonds between carbon atoms. Carbon compounds also are known as organic com-pounds. Many molecules in living things are very large. Very large molecules are called macromolecules. Macromolecules form through polymerization. In this process, smaller units, called monomers, join to form macromolecules, called polymers.Four groups of organic compounds found in living things are carbohydrates, lipids, nucleic acids, and proteins.Carbohydrates(starches and sugars) are compounds of carbon, hydrogen, and oxygen. Living things use carbohydrates as their main energy source. Plants and some animals also use carbohydrates for structural purposes. Simple sugars are called monosaccharides.When two or more monosaccharides join, they are called polysaccharides.Lipids(fats, oils, and waxes) are made mostly of carbon and hydrogen. Lipid molecules are made up of compounds of fatty acids and glycerol.In the body, lipids are used to:•store energy•form parts of membranes•form waterproof coveringsNucleic acids contain hydrogen, oxygen, nitrogen, carbon, and phosphorus. Nucleic acids store and transmit hereditary,or genetic, information.There are two kinds of nucleic acids: DNA and RNA.Proteins are made of nitrogen, carbon, hydrogen, and oxygen. Proteins are polymers of amino acids.Proteins are used to:•control the rate of reactions•regulate cell processes•help form bones and muscles•carry substances into or out of cells•help fight disease2–4 Chemical Reactions and EnzymesEverything that happens in an organism is based on chemical reactions. A chemical reaction is a process that changes one setof chemicals into another set of chemicals. The elements or com-pounds that enter into the reaction are the reactants.The elements or compounds produced by the reaction are known as products. Chemical reactions always involve breaking the bonds in reactants and forming new bonds in products.Some chemical reactions release energy; others absorb energy. Chemical reactions that release energy often occur sponta-neously. Chemical reactions that absorb energy require a source of energy.Every chemical reaction needs energy to get started. The energy that starts a chemical reaction is called activation energy.Some chemical reactions that make life possible are too slow.A catalyst is a substance that speeds up the rate of a chemical reaction. Catalysts work by lowering a reaction’s activation energy.Enzymes are proteins that act as biological catalysts. Enzymes speed up chemical reactions that take place in cells.In an enzyme-catalyzed reaction, the reactants are known as substrates. Substrates bind to a site on the enzyme called an active site. The fit of substrates binding to an active site is so specific that they are often compared to a lock and key. Substrates remain bound to the enzyme until the reaction is done. Once the reaction is over, the products are released.。
Quantum Chemistry-Chapter 2
Figure 2-2 Allowed energies for a particle in various one-dimensional potentials.(a)―box‖withinfinitewalls.(b)quadraticpotential,V=1/2 kx2. (c) V =−1/ |x|.
Chapter 2 Quantum Mechanics ofΒιβλιοθήκη Some Simple Systems
2-1 The Particle in a OneDimensional “Box”
2-1 2-2
Figure 2-1
Possible solution: sin(kx), cos(kx), and exp(±ikx)
2-2.A Energies (1) The most obvious feature of the energies is that, as we move through the allowed states (n = 1, 2, 3, . . . The number n is called a quantum number.), E skips from one discrete, well-separated value to another (1, 4, 9 in units of h2/8mL2). Thus, the particle can have only certain discrete energies—the energy is quantized. nondegenerate
E =p2/2m=n2h2/8mL2 2-12
2-2.B Wavefunctions
Physical chemistry of surfaces and interfaces
Physical chemistry of surfaces andinterfaces物理化学在表面与界面上的应用表面和界面是物理化学研究的重要方向之一。
表面和界面在化学反应、催化、传质、生物分子识别、核磁共振、半导体和薄膜技术以及材料科学和纳米技术方面具有重要的应用。
液体或气体与固体相互作用的界面成为“物理界面”和“化学界面”。
物理化学研究旨在研究物理界面和化学界面，特别是它们在科学和工业中的应用。
这篇文章将讨论表面和界面的一些基本特性和物理化学原理。
表面和界面的基本特性表面是固体和气体/液体接触的部分。
表面分为晶体表面和非晶体表面。
晶体表面由原子、分子或离子行成的晶体粗糙面组成。
非晶体表面由分子、原子和离子组成的表面组成。
在固体表面上，表面分子可以形成单层或多层细胞膜。
界面可以是固体和气体的交界面或固体和液体的交界面。
表面和界面影响到一系列诸如吸附、催化、润滑、光电产生、防锈、阻燃、化学传感、膜分离等方面的问题。
物理化学原理和应用表面和界面的物理化学性质受到了热力学和动力学的影响。
热力学研究相变和能量的转移。
相变包括固液相变（熔化和凝固），液气相变（沸腾和凝华）和固气相变（升华和凝华）。
随着相变，表面和界面的能量也会发生变化。
例如，在固液界面，热能从热力学上产生。
在液气界面，表面张力阻止了气体的升华。
动力学研究物质运动的速率，这在表面和界面的催化反应和毒化反应方面非常重要。
催化是化学反应的一种方式，可增加反应速率并节省能源。
催化反应通过降低反应的活化能（Ea），并且通常在表面和界面上发生。
催化剂也可以用于去除有毒物质。
例如，催化剂可将一氧化碳（CO）转化为二氧化碳（CO2），并消除空气中的有毒物质。
在纳米技术和材料科学中，表面和界面也扮演着重要角色。
表面积与体积成正比例，因此在微小尺度下，表面积达到巨大，其性质对材料性质起决定性作用，例如热扩散、分子光电产生、氧化、钝化等。
因为固体相对比表面体积很大，所以固体中的物理和化学性质通常很不同。
PHYSICAL CHEMISTRY (THEORETICAL CHEMISTRY)
解释: (1) T 恒定时, pVm = 常数, 意味着 p , Vm 0. (2) p = (n/V)RT, 表明在恒温下, 气体分子碰撞器壁的压 力与分子数密度成简单的比例关系, 可见每一分子碰 撞器壁的动量变化不受气体密度(或气体分子间距)的 影响, 而这只有在分子间没有相互作用时才有可能. 理想气体状态方程近似适用于低压实际气体. 易液化气 体的适用压力范围较窄, 难液化气体则相对较宽.
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ห้องสมุดไป่ตู้
• 波义耳定律的一个应用 —— 气压水井
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理想气体状态方程
波义尔定律 盖 吕萨克定律 pV = 常数 V / T = 常数 (n, T 恒定) (n, p 恒定) (T, p 恒定) • 相同质量, 温度 和压力时He 和 He 0.6g/L Ar 具有不同的 体积(和密度). 两种气体的 体积与其物质 Ar 1.6g/L 的量成正比.
阿伏加德罗定律 V / n = 常数 • 气球在液氮 冷却作用下 体积减小
理想气体状态方程: 上述三经验定律相结合, 得到 pV = nRT
式中 R 为摩尔气体常数, 数值为8.314，单位 Jmol-1 K-1 .
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理想气体模型
理想气体: 凡在任何温度、压力下均服从理想气体状态方程 的气体称为理想气体. 理想气体的两个特征: (1)分子本身必定不占有体积; (2)分子间无相互作用.
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2.任务：
1）在于采用物理学的原理、实验方法与数学手段 来研究在化学变化中引起物理条件的变化，或称 为伴随着物理变化，采用不同的物理条件引起不 同的化学反应结果的规律与原因； 2）研究重新组合到底经过什么途径？有什么规律？ 为什么要经过这一途径？等等， 这些需要从理论上进行解释。热力学和动力 学中可找到部分答案。 由此种种因素的促使，物 理化学的形成势在必行。
physical chemistry chemical physics 9篇 -回复
physical chemistry chemical physics 9篇-回复Physical Chemistry Chemical Physics (PCCP) is a scientific journal that focuses on the field of physical and theoretical chemistry. In this article, we will explore several key topics related to PCCP, including its scope and impact, the review and publication process, the importance of interdisciplinary research, and emerging trends in the field. By the end of this article, you will have a comprehensive understanding of the world of physical chemistry chemical physics.PCCP, as mentioned earlier, is a renowned scientific journal that plays a crucial role in advancing the field of physical chemistry. Its primary scope includes experimental, theoretical, and computational research in areas such as chemical physics, physical chemistry, biophysical chemistry, and materials chemistry. The journal aims to provide a platform for scientists to share their latest discoveries and advancements in these disciplines and promote the exchange of ideas among researchers worldwide.The impact of PCCP can be measured in various ways. Firstly, it has a high journal impact factor, indicating that articles published in PCCP are frequently cited by other researchers, thus demonstrating the journal's influence and significance in the scientific community.Additionally, PCCP is indexed in numerous databases, making its content easily accessible to researchers and students alike. This wide circulation further enhances its impact and visibility within the scientific community.The review and publication process of PCCP follows a rigorous, double-blind peer-review system. Upon submission, the manuscript is carefully examined by the editorial team to ensure it meets the journal's criteria and scope. If approved, the paper is then sent to two independent reviewers who assess its scientific validity, originality, and relevance. Based on their feedback, the authors may be asked to revise and resubmit their work for further evaluation. This iterative process ensures that only high-quality research is accepted for publication.Interdisciplinary research is highly encouraged in PCCP. The integration of multiple disciplines leads to new insights and breakthroughs that would not be possible within the confines of one field. Physical chemistry chemical physics encompasses diverse areas such as biophysics, materials science, and theoretical chemistry, making collaboration among scientists from different backgrounds vital. By fostering interdisciplinary studies, PCCPpromotes innovation and allows for the exploration of complex scientific phenomena from multiple perspectives.A notable trend in PCCP is the increasing utilization of computational methods in research. With the rapid advancement of computing power, scientists can now simulate molecular structures and reactions with unprecedented accuracy. Computational chemistry enables researchers to investigate complex systems and phenomena that are difficult or impossible to study experimentally. This approach not only expands the boundaries of knowledge but also serves as a valuable tool for experimentalists in designing and optimizing experiments.Another emerging trend is the focus on sustainable chemistry and renewable energy. As the world grapples with environmental challenges, researchers are actively seeking alternative energy sources and sustainable materials. PCCP plays a crucial role in this endeavor by publishing studies on green and clean energy solutions, such as solar cells, fuel cells, and catalysis. By disseminating this knowledge, PCCP contributes to the development of a more sustainable future.In conclusion, Physical Chemistry Chemical Physics (PCCP) is a prestigious journal that serves as a platform for scientists to share their research in physical and theoretical chemistry. Its impact and influence are evident in its high journal impact factor and widespread indexing. The review and publication process follow a meticulous peer-review system to ensure the quality and validity of the research. PCCP encourages interdisciplinary collaboration, allowing for the exploration of complex scientific phenomena. Current trends in the field include the increased utilization of computational methods and the emphasis on sustainable chemistry and renewable energy. By staying abreast of these trends, PCCP continues to contribute to advancements in physical chemistry chemical physics and shape the future of scientific research.。
physical_Chemistry2010
3. Electrochemistry 电化学
Electrolyte Degree of ionization (电离度) 电离度) Ionization constant Ionic strength (离子强度) 离子强度) Ionic product
Conductivity Electrode Reversible/ Irreversible electrode Reference / Working electrode Redox electrode Metal electrode Gas electrode Membrane electrode
• Phase equilibrium （相平衡） 相平衡） • Number of components K=SK=S-R-R’ （组分） 组分） • Degree of freedom (f) （自由度） 自由度） • Phase rule, number of phase=K+2-f （相律） phase=K+2相律） • Phase change, phase transition （相变） 相变） • Phase diagram （相图） 相图） • Triple point （三相点） 三相点） • Critical state (临界状态) (临界状态 临界状态) • Critical phenomenon/constant / point/temperature
Physical chemistry 物理化学
Physical Chemistry is the branch of chemistry that concerns the physical and chemical properties of matter, and it is also essential for developing the modern techniques used to determine the structure and properties of matter, such as new synthetic materials and biological macromolecules.
华中师范大学化学专业英语课件5
厦门大学固体表面物理化学国家重点实验室
8.3 Oxidation-Reduction reactions
• Although the above-discussed reaction classes are useful, there are other ways to group chemical reactions. For instance, reactions can be classified according to to whether or not electrons are transferred as the reactants are converted to products.
厦门大学固体表面物理化学国家重点实验室
•Oxidation Numbቤተ መጻሕፍቲ ባይዱrs
Oxidation numbers are charges assigned to atoms by assuming that all the bonded electrons are associated with the more electronegative atom. These oxidation numbers serve as a “bookkeeping” (簿记) device to keep track of electrons that are transferred in a chemical reaction.
物理化学(PPT资料优秀版
分离——相平衡，相际扩散，界面现象
物料输送——pVT关系
物理化学（ PHYSICAL CHEMISTRY）
西南科技大学
物理化学研究：
平衡规律——当系统的一个平衡态由 于条件改变而变为另一个平衡态时，能量、 体积和各物质的数量变化的规律。
宏观变化，而不涉及变化的细节。
对固体构效关系的认识的深入，已能对固体表面“整容”，催化由技艺性走向科学化；
(4) 从单一学科到交叉学科
物理化学运用数学、物理学等基础科学的理论和实验方法，研究化学变化包括C相2变H化3C和l pVT变化中的平衡规律和速率规律，以及这些
规律与物质微观结构的关系。
(精馏塔）
物理化学（ PHYSICAL CHEMISTRY）
西南科技大学
平衡和速率是制备和性能研究中最基 本的问题。对于化工包括冶金、轻工来说， 有利的平衡和速率是实现化学物质和材料 的大规模生产的前提。前者决定理论的产 率，后者决定实际的产量。
物理化学（ PHYSICAL CHEMISTRY）
西南科技大学
进行定量监测。
(精馏塔）
C2H3Cl
(裂解炉）
氯乙烯生产工艺流程
物理化学（ PHYSICAL CHEMISTRY）
西南科技大学
Cl2
H2
FeCl3 &#衡体系。 三个层次——宏观，从微观到宏观，微观
C2H4
4
近代化学的发展趋(势电和解特槽点）
(反应器）
物理化学是研究化学体系最一般的宏观、微观 规律的学科，特别是给出定量化规律。一般方 法是根据实验事实建立物理模型，应用数学原 理进行严密的或近似的推演得到公式。
应用化学专业英语朱红军第二版课文翻译
应用化学专业英语朱红军第二版课文翻译Unit 7 Physical ChemistryPhysical chemistry is the study of the physical basis of chemical systems and processes. Modern physical chemistry is firmly grounded upon physica. Important areas of study include chemical thermodynamics, chemical kinetics, quantum chemistry, statistical mechanics, electrochemistry, surface and solid state chemistry, and spectroscopy.物理化学是对化学系统和过程的物理基础的研究。
现代物理化学以物理为基础。
重要的研究领域包括化学热力学、化学动力学、量子化学、统计力学、电化学、表面和固体化学以及光谱学。
We have repeatedly referred to the energy effects accompanying chemicaland physical changes. Thermodynamics is the study of these energy effects in particular, it summarizes the relations between heat, work, and other forms of energy that are involved in all types of changes. The laws of thermodynamics can be used to predict whether a particular chemical or physicaltransformation is theoretically possible under a given set of conditions. Furthermore, if a study shows that a desired change will not occur under the conditions assumed, thermodynamic principles can be used to determine how the conditions can be altered to make the change theoretically possible.我们一再提到伴随着化学和物理变化的能量效应。
2-2热力学基本概念及术语2
Physical Chemistry（上册）物理化学（上册）绪论第一章气体第二章热力学第一定律第三章热力学第二定律第四章多组分系统热力学第五章化学平衡第六章相平衡第二章热力学第一定律The first law of thermodynamics§2-1 热力学基本概念及术语The of thermodynamic concepts and term１．过程：系统状态发生的任何变化２．途径：系统状态发生变化过程的具体历程３．热力学常见过程分类：(1)纯pＶＴ变化、相变化、化学变化过程纯pＶＴ变化：无相变化、无化学反应变化相变化：有相变化、无化学反应变化化学变化：有化学反应的变化§2-1 热力学基本概念及术语五、过程和途径§2-1 热力学基本概念及术语The of thermodynamic concepts and term(2)可逆过程与不可逆过程可逆过程：在一系列无限接近平衡条件下进的过程，每一步变化无穷小，马上达到平衡。
理解可逆过程是学好化学热力学的重点和难点(3)循环过程与非循环过程循环过程：终态与始态相同的过程循环过程特点：系统所有状态函数变化量为0§2-1 热力学基本概念及术语五、过程和途径§2-1 热力学基本概念及术语The of thermodynamic concepts and term(4)按pＶＴ变化性质分为恒温、恒压、恒容、恒外压、绝热过程恒温：系统温度一直不变。
简单判断方法：T1=T2=T(环)=常数恒压：系统压力一直不变。
简单判断方法：p1=p2=p(环)=常数恒容：系统的体积一直不变。
简单判断方法：V=常数恒外压：环境压力保持不变。
简单判断方法：p(环)=常数绝热过程：系统与环境没有热交换。
Q=0.§2-1 热力学基本概念及术语五、过程和途径§2-1 热力学基本概念及术语The of thermodynamic concepts and term§2-1 热力学基本概念及术语五、过程和途径§2-1 热力学基本概念及术语The of thermodynamic concepts and term在系统变化过程中才产生的函数叫过程函数或途径函数。
Levine、McQuarrie和Simon编写的两本经典物理化学英文教材介绍
Univ. Chem. 2023,38 (6), 129–133129•专题•doi: 10.3866/ Levine、McQuarrie和Simon编写的两本经典物理化学英文教材介绍侯文华1,*，张树永21南京大学化学化工学院，南京2100232山东大学化学与化工学院，济南250100摘要：从编写指导思想、主要内容和章节编排、主要特色、存在的不足等多个维度，对Levine编写的Physical Chemistry (6th edition)以及McQuarrie和Simon编写的Physical Chemistry-A Molecular Approach两本英文教材进行了较为全面的介绍，对国内物理化学教材建设具有一定的启示和借鉴作用，也有利于国内物理化学相关课程师生了解、学习和使用这两本教材。
关键词：Levine编写的物理化学第6版；McQuarrie和Simon编写的《物理化学——一种分子途径》；物理化学教材；介绍；教材建设中图分类号：G64；O642.1An Introduction to Two Classical English Physical Chemistry Textbooks Compiled by Levine, McQuarrie and SimonWenhua Hou 1,*, Shuyong Zhang 21 School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China2 School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China.Abstract: Two classical physical chemistry textbooks, Physical Chemistry(6th edition) by Levine and Physical Chemistry-A Molecular Approach by McQuarrie and Simon, are comprehensively introduced from several aspects including guiding principles of textbook compilation, main contents, chapter and section arrangements, main features, and some shortcomings. This paper can provide certain revelation and reference for the construction of domestic physical chemistry textbooks, and is also helpful for the teachers and students in the physical chemistry related courses to understand, study and use these two books.Key Words: Physical Chemistry (6th edition) by Levine;Physical Chemistry-A Molecular Approach by McQuarrie and Simon; Physical chemistry textbook;Introduction; Textbook construction由美国纽约城市大学化学系Ira N. Levine教授编写的Physical Chemistry以及由美国加州大学Davis分校Donald A. McQuarrie和杜克大学John D. Simon两位教授编写的Physical Chemistry-A Molecular Approach是两本经典的物理化学英文教材[1,2]，在国内外有重要的影响，不少教师将这两本教材作为物理化学课程的指定教材或参考书。
物理化学ⅡPHYSICALCHEMISTRY18
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以多孔铜为集流体制备Cu_6Sn_5合金负极及其性能
[Article]物理化学学报(Wuli Huaxue Xuebao )Acta Phys.-Chim.Sin .,2009,25(4)：611-616April Received:October 31,2008;Revised:January 7,2009;Published on Web:February 11,2009.*Corresponding authors.Email:fandajiao@,sgsun@.国家重点基础研究发展规划(973)项目(2009CB220102)资助鬁Editorial office of Acta Physico -Chimica Sinica以多孔铜为集流体制备Cu 6Sn 5合金负极及其性能樊小勇1,2,*庄全超2魏国祯2柯福生2黄令2董全峰2孙世刚2,*(1长安大学材料科学与工程学院,西安710061;2厦门大学化学化工学院化学系,固体表面物理化学国家重点实验室,福建厦门361005)摘要：以氢气泡为动力学模板电沉积获得多孔铜,并通过热处理增强其结构稳定性.进一步将多孔铜作为基底通过电沉积制备Cu -Sn 合金负极.XRD 结果给出其组成为Cu 6Sn 5合金,扫描电子显微镜(SEM)观察到Cu 6Sn 5合金电极为三维(3D)多孔结构.充放电结果指出,Cu 6Sn 5合金电极具有较好的充放电性能,其首次放电(嵌锂)和充电(脱锂)容量分别为735和571mAh ·g -1,并且具有较好的容量保持率.运用电化学阻抗谱研究了Cu 6Sn 5合金电极在商业电解液中的界面特性.关键词：多孔铜集流体;Cu 6Sn 5合金;锂离子电池;负极;电化学阻抗谱中图分类号：O646Fabrication and Performance of Cu 6Sn 5Alloy Anode Using Porous Cu as Current CollectorFAN Xiao -Yong 1,2,*ZHUANG Quan -Chao 2WEI Guo -Zhen 2KE Fu -Sheng 2HUANG Ling 2DONG Quan -Feng 2SUN Shi -Gang 2,*(1School of Materials Science and Engineering,Chang ′an University,Xi ′an 710061,P.R.China ;2State Key Laboratory forPhysical Chemistry of Solid Surfaces,Department of Chemistry,College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361005,Fujian Province,P.R.China )Abstract ：Porous Cu was fabricated by electrodeposition through a kinetic template of hydrogen bubbles.The product was subsequently annealed to increase its structural stability.The Cu -Sn alloy was then electrodeposited onto porous Cu which served as a current collector.X -ray diffraction (XRD)studies ascertained that the composition of the Cu -Sn alloy was Cu 6Sn 5and scanning electron microscopy (SEM)investigations showed a three -dimensional (3D)porous structure of the electrode.The first charge/discharge capacities of the Cu 6Sn 5alloy electrode were measured respectively at 735and 571mAh ·g -1,and a good retention of the capacities has been determined.Interfacial properties of the Cu 6Sn 5alloy electrode in a commercial electrolyte were also studied by electrochemical impedance spectroscopy (EIS).Key Words ：Porous Cu current collector;Cu 6Sn 5alloy;Lithium ion battery;Anode;Electrochemicalimpedance spectroscopy锂离子电池以其高能量密度、长循环寿命和环境友好等优点不仅广泛作为手机、笔记本电脑、数码照相机和数码摄像机等便携式电子设备的电源,而且在电动工具、电动助力车以及电动汽车等领域显示出良好的应用前景.目前商品化锂离子电池主要采用石墨类碳为负极材料.但石墨类碳负极材料已611Acta Phys.-Chim.Sin.,2009Vol.25几乎达到其理论比容量(372mAh·g-1),不能满足日益增长的对锂离子电池高比容量的需求.锡金属具有质量比容量和体积比容量大等优点,受到广泛关注和研究[1].但锡金属在与锂合金化的过程中会产生巨大的体积膨胀,造成活性材料粉化、脱落,活性材料与基底间的电子接触电阻增大,最终导致容量衰减速度增大[2,3].研究发现,当其它活性元素(如Sb)[4-7]和非活性元素(如Cu,Co,Ni等[8-13])与锡形成合金后,电极与锂合金化过程中的体积膨胀可以得到一定程度的缓解.其中Cu6Sn5合金以其导电性好,价格便宜等优点,被认为是最具潜力的合金负极材料之一[14-17].目前对Cu6Sn5合金的合成已有大量研究文献报导,包括纳米粒子、薄膜材料以及多孔合金等.研究发现,采用具有三维(3D)结构的集流体不仅可缓解锡基合金电极在充放电过程中的体积变化,而且可改善合金电极的高倍率充放电性能.Jiang等[18]指出,将非活性碳填充到表面覆盖锡金属的通过氢气模板法制得的多孔铜表面,然后经过热处理得到Cu-Sn合金,可很大程度上抑制合金电极容量衰减. Mastragostino等[19]将Cu6Sn5合金电沉积在具有三维多孔结构的碳纸上,也获得了较好的电化学性能. Scrosati等[20]最近将Sn-Ni合金电沉积到通过氧化铝模板制得的三维柱状铜阵列上,显示该三维结构可缓解Sn-Ni合金电极在充放电过程中的体积变化,达到改善其循环性能的目的,经过200周循环后容量可保持500mAh·g-1左右.Zhao等[21]运用相分离法在铜基底上制得微孔聚丙烯腈(PAN)膜,然后将Cu和Sn共沉积到微孔内,经过热处理得到Cu-Sn合金.研究结果给出该Cu-Sn合金作为锂离子电池负极表现出稳定的循环性能.我们在前期的研究中也发现,采用多孔泡沫铜为集流体的Cu6Sn5合金电极具有比以光滑铜片集流体的Cu6Sn5合金电极更好的循环性能[22].本文以氢气模板法首先制备多孔铜,然后在适当的温度下热处理增强其结构稳定性.再将热处理后的多孔铜作为基底,通过电沉积制备具有三维多孔结构的Cu6Sn5合金电极.运用XRD、扫描电子显微镜、充放电测试和电化学阻抗谱研究Cu6Sn5合金电极的结构、表面形貌、充放电性能及其与商业电解液的相容性.1实验1.1多孔铜的制备在含有5.0mol·L-1硫酸铜、4.0mol·L-1硫酸、0.5mmol·L-1氯化钠、20mg·L-1聚乙二醇(PEG)的电沉积溶液中(以上试剂均为分析纯),以镀铂钛网为阳极,铜片为阴极(基底),电流密度为0.4A·cm-2条件下电镀2min获得多孔铜;以氢、氩混合气(约5%H2和95%Ar)为保护气,在300℃下热处理8h,然后在700℃下热处理1h得到结构稳定的多孔铜.1.2Cu6Sn5合金电极的制备将热处理后的多孔铜作为基底,电沉积制得Cu6Sn5合金.电沉积工艺参数为,20g·L-1SnCl2·2H2O,4.0g·L-1CuSO4·5H2O,180g·L-1K2P2O7,1g·L-1添加剂a,1g·L-1添加剂b,0.1g·L-1添加剂c(添加剂a、b、c所含具体物质见文献[23]),常温,电流密度为0.5A·dm-2,电沉积时间为5min,其中添加剂a、b、c的加入可以将Sn和Cu的沉积电位拉近,且可以起到稳定镀液的作用.电镀Cu-Sn合金前后,分别对多孔铜进行称量,两次质量之差即为Cu-Sn 合金的质量.1.3Cu6Sn5合金电极的表面形貌和结构表征XRD分析在X′pert PRO X射线衍射仪(荷兰Panalytical分析仪器)上完成,以Cu靶Kα线为辐射源,管电压40kV,管电流30mA,扫描范围20°-90°,步长0.016°,每步时间15s.样品的SEM形貌观察在LEO1530型扫描电子显微镜(德国LEO电镜有限公司)上完成.1.4Cu6Sn5合金电极的电化学性能测试以锂片为负极,Cu6Sn5合金为正极,LiPF6-碳酸乙烯酯(EC):碳酸二甲酯(DMC):碳酸二乙酯(DEC) (体积比为1∶1∶1,张家港国泰华荣化工新材料有限公司)为电解液,Celgard2300为隔膜,在充满氩气的手套箱中组装成2025型扣式电池,然后在新威BTS高性能电池测试仪上,以50mA·g-1的电流进行充放电测试.电极的质量比容量以Cu6Sn5合金镀层总的质量为活性质量计算而得.锂片作为辅助电极和参比电极,以Cu6Sn5合金为研究电极,LiPF6-EC∶DMC∶DEC(体积比为1∶1∶1)为电解液,在自制玻璃三电极体系中,用PARSTAT2263综合电化学测试仪(PRINCETON,Co.,American)进行电化学阻抗谱测试.电化学阻抗实验中的频率范围为105-10-2 Hz,施加的交流信号振幅为5mV.在进行阻抗测试前,电极在极化电位平衡1.5h.2结果与讨论612No.4樊小勇等：以多孔铜为集流体制备Cu 6Sn 5合金负极及其性能2.1Cu 6Sn 5合金电极的表面形貌和结构图1给出未经热处理的多孔铜(a,b)、经过热处理后的多孔铜(c,d)以及电沉积制得的Cu 6Sn 5合金(e,f)的SEM 图.由图可观察到,未经过热处理的多孔铜由大量100μm 左右大小的三维孔洞组成(图1a),孔壁上有大量枝晶(图1b).该结构的稳定性较差,易与基底剥离,所以不宜直接作为电极集流体.当多孔铜经过热处理后(图1c),表面形貌发生较大变化,主要由于经过热处理后原来疏松的枝晶结构变得致密所致.从经过热处理后的多孔铜的高倍率SEM 图(图1d)可观察到,虽然多孔铜的整体结构有很大程度的变化,但是多孔铜的孔壁仍然由大量不规则孔洞组成,且枝晶基本消失,结构稳定.在热处理后的多孔铜上电沉积Cu 6Sn 5合金(图1(e,f))后,电极仍然保持3维多孔结构.该结构不仅可提供足够的空间容纳Cu 6Sn 5合金电极在嵌锂过程的体积膨胀,而且可减小活性材料与基底间的应力,防止活性材料的龟裂、粉化、脱落,确保多孔铜基底与活性材料间具有良好的电接触,最终达到提高电极循环性能的目的.在热处理后的三维多孔铜集流体上电沉积Cu -Sn 合金的XRD 图如图2所示.可观察到电沉积层主要由3个不同的相组成:一是主要的电沉积产物Cu 6Sn 5合金(JCPDS No.00-045-1488,单斜晶型,空间群为C 2/c ),另两个分别是少量四方晶型的Sn (JCPDS No.65-0296)和基底铜.2.2三维多孔Cu 6Sn 5合金电极的充放电性能图3和图4分别为所制备的Cu 6Sn 5合金电极的充放电曲线、循环性能曲线和相应的微分容量曲线.从充放电曲线(图3(a))和其相应微分容量曲线(图4)可观察到,首次放电过程中在0.32V 以上(Cu 6Sn 5合金嵌锂之前)产生了大约75mAh ·g -1的不可逆容量,这是由于该合金电极表面积大,电解液在其表面还原分解严重所致;由首次放电曲线和其相应微分容量曲线还可得到,首次放电过程中该电极在约0.32和0.00V 分别给出电位平台.其中0.32V 附近的电位平台从第2周循环开始正移至0.40V 附近,在随后的循环中无明显变化,表征Cu 6Sn 5合金相转变为Li 2CuSn 合金相过程.当电极经过20周循环后这一电位平台明显变短,且在0.17V 附近出现了一个新的电位平台.由充放电曲线还可观察到20周循环后在电位大于0.40V 处出现了放电容量.当电极循环50周后,在0.20V 以上基本变为一条斜线,然后在0.17V 附近的电位平台变长.由图3(a)和图4还可观察到Cu 6Sn 5合金电极的充电(脱锂)曲线的平台电位无明显变化,但当电极循环20周后,0.75V 附近的电位平台变短,随着循环次数增加进一步变短,这与放电曲线相对应.Cu 6Sn 5合金电极的充放电循环性能曲线由图3(b)给出,测得Cu 6Sn 5合金电极的首次放电容量为735mAh ·g -1,首次充电图1未经过热处理多孔铜(a,b)、热处理后多孔铜(c,d)及电沉积获得的Cu 6Sn 5合金(e,f)的SEM 图Fig.1SEM images of as -deposited porous Cu (a,b),annealed porous Cu (c,d)and Cu 6Sn 5alloy (e,f)onthe annealed porous Cu613Acta Phys.-Chim.Sin.,2009Vol.25容量为571mAh·g-1;第2周至第11周循环容量迅速下降,放电和充电容量分别下降到411和395 mAh·g-1;从11周循环开始,容量降低速度明显减缓,经过50周循环后放电和充电容量分别保持在361和342mAh·g-1,其容量保持率(相对于第11周循环容量)分别为88%和87%.图3(b)给出首次库仑效率为78%,随着循环次数的增加,迅速增加至95%左右,最后基本稳定在该数值.2.3三维多孔Cu6Sn5合金电极的阻抗特性图5给出三维多孔Cu6Sn5合金电极在室温下,首次嵌锂过程的阻抗谱(Nyquist图).可观察到,开路电位2.700V时的Nyquist图由一个曲率半径很大的圆弧组成,表现为阻塞电极特征,即无锂离子的嵌入/脱出.当电极电位极化到1.000V时,Nyquist图中的高频区域给出一段圆弧,说明电解液开始在Cu6Sn5合金电极上还原分解生成固体电解质相界面膜(SEI膜)覆盖于电极表面.当电极电位降低到0.400 V时,Nyquist图转变为由三部分组成,即高频圆弧、中频圆弧和低频曲率半径很大的圆弧.进一步降低电极电位,高频和中频圆弧变化不大,低频圆弧逐渐转变为一条斜线,至0.275V时完全转变为一条斜线.当电极电位降低到0.100V后,中频圆弧完全分614No.4樊小勇等：以多孔铜为集流体制备Cu6Sn5合金负极及其性能离出来,同时低频斜线开始弯曲为一段圆弧;当电极电位进一步降低直至嵌锂完毕(0.025V)时,Nyquist 图均无明显变化.根据文献并结合实验结果可得出,高频圆弧代表锂离子穿过电极表面SEI膜的阻抗[24-26],中频圆弧代表电荷传递阻抗,低频圆弧代表相变阻抗[27-30].庄全超等[31,32]在对LiCoO2和LiMn2O4的研究中也获得三段圆弧的阻抗谱,并将中频圆弧归结于电子阻抗,低频圆弧则归属电荷传递阻抗.但对于Cu6Sn5合金电极而言,电子电导率很高,所以Nyquist图中不可能出现代表电子阻抗的圆弧;同时如果将低频圆弧归结于电荷传递阻抗的话,其曲率半径应该随电极电位的降低而减小,而实验结果是在整个嵌锂电位区间内其曲率半径很大,且随电极电位降低逐渐转变为一条直线,然后再次转变为一段圆弧,这一现象不符合电荷传递阻抗的特征.同时我们从充放电曲线中可观察到在0.400V附近给出一个明显的电位平台,对应于Cu6Sn5相转变为Li2CuSn相,由于产生了新的Li2CuSn相,所以出现了新的Cu6Sn5/Li2CuSn相界面,且由于Cu6Sn5相和Li2CuSn相的物理化学性质差别很大,特别是体积和密度变化很大,导致在阻抗谱中的时间常数有较大差别,最终产生了低频圆弧.当电位降低到0.325 V时,由于相变不明显导致低频圆弧转变为代表扩散的斜线.当电极电位降低到0.100V以下时,由于出现了新的相变(Li2CuSn相转变为Li4.4Sn相),因此低频区域又出现了新的圆弧.石墨、LiCoO2和LiMn2O4体系中锂离子是在二维(石墨和LiCoO2)和三维通道(LiMn2O4)中传输,体积变化较小,体相内部物理化学性质变化不大,未出现明显的相界面,所以并不出现代表相变阻抗的圆弧,低频区域只出现代表体相扩散的斜线.3结论以氢气泡为模板电沉积制得多孔铜,通过热处理增强了其结构稳定性,并用作Cu6Sn5合金电极的集流体.充放电结果显示该多孔结构可缓解Cu6Sn5合金电极充放电过程中的体积变化,显著改善其循环性能,测得其首次放电容量为735mAh·g-1,首次充电容量为571mAh·g-1,第2周至第11周循环容量迅速下降,随后容量衰减速度迅速减慢,经过50周循环后放电和充电容量保持率分别为88%和87%(相对于第11周循环容量).运用电化学阻抗谱研究了Cu6Sn5合金电极与商业电解液的界面特性,发现其在主要的放电区间内,Nyquist图中出现了代表相变阻抗的圆弧.References1Idota,Y.;Kubota,T.;Matasufuji,A.;Maekawa,Y.;Miyasaka,T.Science,1997,276:13952Winter,M.;Besenhard,J.O.Electrochim.Acta,1999,45:313Besenhard,J.O.;Yang,J.;Winter,M.J.Power Sources,1997,68: 874Shi,L.H.;Li,H.;Wang,Z.X.;Huang,X.J.;Chen,L.Q.J.Mater.Chem.,2001,11:15025Li,H.;Wang,Q.;Shi,L.H.;Chen,L.Q.;Huang,X.J.Chem.Mater.,2002,14:1036Chen,W.X.;Lee,J.Y.;Liu,mun.,2002,图5三维多孔Cu6Sn5合金电极在室温下首次嵌锂过程的阻抗谱(Nyquist图)Fig.5Electrochemical impedance spectroscopies(EIS)of3D porous Cu6Sn5alloy electrode duringinitial 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2.1 纳米材料的表面原子
表面原子数 （总）体原子数
x 100%
表面/ 表面/体原子数比率与直径的关系
100
Surface atoms [%]
80 (1.2nm, 76%) 60 (5nm, 45%) 40 (7nm, 35%) (63µm, ~0%)
20
0 0.1 1 10 100 104 105
降低表面能的途径
（1）表面驰豫，表面原子或离子向体内偏移，这种过程在液相中很容 表面驰豫，表面原子或离子向体内偏移， 易发生，而固态表面由于其刚性结构难度有所提高； 易发生，而固态表面由于其刚性结构难度有所提高； 表面重构，通过结合表面悬挂键形成新的化学键； （2）表面重构，通过结合表面悬挂键形成新的化学键； （3）表面吸附，通过物理或化学吸附外部物质到表面，形成化学键或 表面吸附，通过物理或化学吸附外部物质到表面， 弱相互作用如静电或发范德瓦耳斯力； 弱相互作用如静电或发范德瓦耳斯力； 表面固态扩散导致的成分偏析或杂质富集 导致的成分偏析或杂质富集。 （4）表面固态扩散导致的成分偏析或杂质富集。
表面能随粒子尺寸的变化
表2.1， 1克NaCl粒子的尺寸与表面能 Size (cm) 0.77 0.1 0.01 0.001 10-4 (1µm) 10-7 (1 nm) Total Surface Area (cm2) 3.6 28 280 2.8 x 103 2.8 x 104 2.8 x 107 Total Edge (cm) 9.3 550 5.5 x 104 5.5 x 106 5.5 x 108 5.5 x 1014 Surface Energy (J/g) 7.2 x 10-5 5.6 x 10-4 5.6 x 10-3 5.6 x 10-2 0.56 560 Edge Energy (J/g) 2.8 x 10-12 1.7 x 10-10 1.7 x 10-8 1.7 x 10-6 1.7 x 10-4 170
Original {100} surface
(2x1) restructured {100} surface
表 面 重 构
Figure 2.5. Schematic illustrating the (2x1) restructure of silicon (001) surface.
H C H C H C H C H C H C H C H C
单晶的热力学平衡形态
低密勒指数晶面的表面能低；因此， 低密勒指数晶面的表面能低；因此，晶体通常由低指Figure 2.7. Examples of single crystals with thermodynamic equilibrium shape. Top-left: sodium chloride, top-right: silver, bottom-left: silver, and bottom-right: gold. Gold particles are formed at 1000 °C and some facets have gone through roughening transition.
减小表面能的方法
将单个纳米结构结合成大的结构以降低整个表面积
烧结，是一种用固-固界面替代固-气界面的工艺， 烧结，是一种用固-固界面替代固-气界面的工艺，是通过将单个纳米 结构无间隙地堆积一起并改变形态的一种方法
固态扩散：表面扩散（低温）、体扩散（高温）、晶间-晶界扩散（中温） ）、体扩散 ）、晶间 固态扩散：表面扩散（低温）、体扩散（高温）、晶间-晶界扩散（中温） 蒸发-冷凝：当纳米粒子在处理温度下具有蒸汽压时，蒸发蒸发-冷凝：当纳米粒子在处理温度下具有蒸汽压时，蒸发-冷凝变得十分重要 分散-沉积：当固态分散或部分溶解在液态时，分散-沉积将发生 分散-沉积：当固态分散或部分溶解在液态时，分散粘性流动： 粘性流动：当材料是非晶并处在玻璃转变温度以上时发生粘性流动 位错蠕变：当材料处在机械应力作用时， 位错蠕变：当材料处在机械应力作用时，位错蠕变十分重要 总的来说，在低温（包括室温）时烧结可以忽略，但当材料逐渐被加热， * 总的来说，在低温（包括室温）时烧结可以忽略，但当材料逐渐被加热，通常达到熔点的 70%时其作用明显 考虑到纳米材料的小尺寸具有特别高的表面能， 时其作用明显。 70%时其作用明显。考虑到纳米材料的小尺寸具有特别高的表面能，适中的温度下烧结也会成 为严重的问题
(d)
从一个点画出一个矢量使其长度正比于晶面的表面能、矢量方向垂直于晶面； 从一个点画出一个矢量使其长度正比于晶面的表面能、矢量方向垂直于晶面； 画出一系列晶面使其垂直于每个矢量并处在矢量的末端； 画出一系列晶面使其垂直于每个矢量并处在矢量的末端； 这种几何图代表平衡状态下的晶体形貌，由相互独立的一系列晶面所组成。 这种几何图代表平衡状态下的晶体形貌，由相互独立的一系列晶面所组成。
单个纳米结构团聚， 单个纳米结构团聚，不改变纳米结构本身
烧结, Ostwald熟化（固态中）
A
Sintering (烧结 烧结) 烧结
B
Ostwald ripening 奥斯特瓦尔德熟化) (奥斯特瓦尔德熟化)
Figure 2.9. Schematic showing sintering and Ostwald ripening processes. (A) Sintering is to combine individual particles to a bulk with solid interfaces to connect each other (B) Ostwald ripening is to merge smaller particles into a larger particle. Both processes reduce the solid-gas surface area.
当粒子尺寸从厘米变到纳米时 当粒子尺寸从厘米变到纳米时，表面能变化 7 个数量级 厘米变到纳米 纳米材料中表面能发挥重要的作用——热力学不稳定或亚稳态 热力学不稳定或亚稳态 纳米材料中表面能发挥重要的作用 克服表面能——保护纳米结构和纳米材料，抑制颗粒生长或团聚 保护纳米结构和纳米材料，抑制颗粒生长或团聚 克服表面能 保护纳米结构和纳米材料
Chapter 2. Physical Chemistry of Solid Surfaces
2.1. Introduction 2.2. Surface Energy 表面能 2.3. Chemical Potential as A Function of Surface Curvature 化学势 2.4. Electrostatic Stabilization 静电稳定化 2.4.1. Surface Charge Density 2.4.2. Electric potential at the proximity of solid surface 2.4.3. Van der Waals Attraction Potential 2.4.4. Interactions between two particles: DLVO theory 2.5. Steric Stabilization 空间稳定化 2.5.1. Solvent and Polymer 2.5.2. Interactions between polymer layers 2.5.3. Mixed Steric and Electric Interactions 2.6. Summary
γ {100 } = γ {110 }
1 2 4ε ⋅ 4 ⋅ε = 2 2 a2 a 5 ε = 2 2 a
γ {111 } = 2 3 ⋅
ε
a2
{100}
{110}
{111}
Figure 2.3. Schematic representing low index faces of a face-centered cubic (fcc) crystal structure: (A) {100}, (B) {110}, and (C) {111}.
热力学平衡晶体形态预测
Wulff 图
. 1 1 1 1
(a)
(10) 面
(b)
(11) 面
形态
(c)
Figure 2.8. Conformation for a hypothetical two-dimensional crystal. (a) (10) plane, (b) 11) plane, (c) shape given by the Wulff construction, and (d) Wulff construction considering only (10) and (11) planes. [A.W. Adamson and A.P. Gast, Physical Chemistry of Surfaces, 6th edn. John Wiley & Sons, New York, 1997.]
1 γ = N bερ a 2
ρa 为表面原子密度
Figure 2.2. Schematic showing two new surfaces being created by breaking a rectangular into two pieces.
面心立方结构的表面能
{100}面： 面 {110}面： 面 {111}面： 面
Ostwald熟化，是2个单个纳米结构形成一个大的结构的过程。较大纳 熟化， 个单个纳米结构形成一个大的结构的过程 个单个纳米结构形成一个大的结构的过程。 熟化 米结构的生长以牺牲小纳米结构为代价，直到后者完全消失为止。 米结构的生长以牺牲小纳米结构为代价，直到后者完全消失为止。
* Ostwald成熟化发生在较宽的温度范围内，当纳米结构被分散溶解在一种溶剂时，相对低的温 成熟化发生在较宽的温度范围内， 成熟化发生在较宽的温度范围内 当纳米结构被分散溶解在一种溶剂时， 度下也可进行