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所在平台: Udemy |
课程主页: https://www.udemy.com/course/surface-chemistry/
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**课程名称：** 表面化学 (Surface Chemistry) **课程概述：** 本课程深入探讨了表面化学的核心概念，重点关注发生在固体表面的化学反应，例如固体催化剂表面的反应以及金属的腐蚀。课程解释了“表面”的定义，即固体最外层的顶部。现代科学技术能够研究固体表面约0.5至2纳米的范围，对应着最顶部的两到五层原子。 **核心概念：** * **吸附 (Adsorption):** 指物质存在于表面时，其浓度与相邻本体（bulk）不同，这是一种选择性吸收现象。 * **吸收 (Absorption):** 指物质均匀分布在整个表面的现象。 * **吸附剂 (Adsorbent):** 指吸附现象发生的本体物质。 * **吸附质 (Adsorbate):** 指被吸附在另一种物质表面上的物质。 * **脱附 (Desorption):** 指从吸附表面移除吸附物质的过程。 **吸附类型：** * **物理吸附 (Physical adsorption/Physisorption):** 吸附质通过弱范德华力（Vander Waal's forces）与吸附剂表面结合。 * **化学吸附 (Chemical adsorption/Chemisorption):** 吸附质与吸附剂表面通过类似于化学键的强力结合。 **吸附热 (Enthalpy or heat of adsorption):** 吸附过程通常伴随着能量的释放，因此是放热过程。
Many chemical reactions take place at the surfaces of solids, e.g., at the surface of solid catalysts. Corrosion of metals takes place at their surfaces. Surface means the topmost layer on the very exterior of a solid. Now-a-days, there are ways of studying the top 0.5 to 2 nm, i.e., two to five of the topmost layers of atoms of the solid surface.Adsorption. The existence of a substance at a surface in different concentration than in the adjoining bulk is called adsorption. It is selective absorption.Absorption. It is the phenomenon in which a substance is uniformly distributed all over the surface.Adsorbent. The substance present in bulk, on the surface of which adsorption is taking place is called adsorbent.Adsorbate. The substance which is being adsorbed on the surface of another substance is called adsorbate.Desorption. The process of removing an adsorbed substance from a surface on which it is adsorbed is called desorption.Physical adsorption or physisorption. If the adsorbate is held on a surface of adsorbent by weak Vander Waal's forces, the adsorption is called physical adsorption or physisorption.Chemical adsorption or chemisorption. If the forces holding the adsorbate are as strong as in chemical bonds, the absorption process is known as chemical adsorption or chemisorption.Enthalpy or heat of adsorption. Adsorption generally occurs with release in energy, i.e., it is exothermic in nature.
