Bolina A S, Wolff A J, Brown W A
Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom.
J Chem Phys. 2005 Jan 22;122(4):44713. doi: 10.1063/1.1839554.
Reflection absorption infrared spectroscopy (RAIRS) and temperature programmed desorption (TPD) have been used to investigate the adsorption of methanol (CH(3)OH) on the highly oriented pyrolytic graphite (HOPG) surface. RAIRS shows that CH(3)OH is physisorbed at all exposures and that crystalline CH(3)OH can be formed, provided that the surface temperature and coverage are high enough. It is not possible to distinguish CH(3)OH that is closely associated with the HOPG surface from CH(3)OH adsorbed in multilayers using RAIRS. In contrast, TPD data show three peaks for the desorption of CH(3)OH. Initial adsorption leads to the observation of a peak assigned to the desorption of a monolayer. Subsequent adsorption leads to the formation of multilayers on the surface and two TPD peaks are observed which can be assigned to the desorption of multilayer CH(3)OH. The first of these shows a fractional order desorption, assigned to the presence of hydrogen bonding in the overlayer. The higher temperature multilayer desorption peak is only observed following very high exposures of CH(3)OH to the surface and can be assigned to the desorption of crystalline CH(3)OH.
反射吸收红外光谱法（RAIRS）和程序升温脱附法（TPD）已被用于研究甲醇（CH₃OH）在高度取向热解石墨（HOPG）表面的吸附情况。RAIRS表明，在所有暴露条件下甲醇均为物理吸附，并且只要表面温度和覆盖度足够高，就能形成结晶态的甲醇。使用RAIRS无法区分与HOPG表面紧密相关的甲醇和多层吸附的甲醇。相比之下，TPD数据显示甲醇脱附有三个峰。初始吸附会观察到一个归属于单层脱附的峰。随后的吸附会导致表面形成多层结构，并观察到两个TPD峰，这两个峰可归属于多层甲醇的脱附。其中第一个显示出分数阶脱附，归因于覆盖层中存在氢键。较高温度的多层脱附峰仅在甲醇对表面进行非常高的暴露后才会出现，可归属于结晶态甲醇的脱附。
