【摘要】 探讨了吸附量热技术及其在测定固体表面酸碱性中的应用 .使用NH3 和CO2 为探针分子 ,吸附量热技术能够定量地描述固体表面酸碱中心的数目和强度分布 .结合原位红外光谱 ,还能够详细地了解表面酸碱中心的性质 :金属氧化物表面的Lewis酸中心和碱中心分别是表面配位不饱和的金属离子和氧负离子 ,Br nsted酸中心和碱中心则是金属氧化物表面的羟基 .通过测量吸附热 ,金属氧化物的表面酸碱性强度可与Sanderson电负性关联起来 ,也可以考虑使用Drago参数来描述固体表面的酸碱性 .根据酸碱性与电负性的关系以及对表面配位不饱和离子的要求 ,有可能通过选择合适的复合金属氧化物组成 ,获得具有一定酸 (碱 )量和酸 (碱 )强度的固体酸 (碱 ) .更多还原

【Abstract】 The technique of microcalorimetric adsorption and its application for measurements of surface acidity and basicity have been reviewed. Specifically, the strength and number of surface acid and base sites can be quantitatively titrated by the microcalorimetric adsorption of NH 3 and CO 2 as probe molecules. In addition, in situ infrared spectroscopy provides the information about the nature of the surface acid and base sites. For example, Lewis acid and base sites on metal oxides are coordinatively unsaturated metal cations and oxygen anions, respectively, while Brnsted acid and base sites are the hydroxyl groups on the surface. In addition, the strengths of surface acidity and basicity as defined by the adsorption heat of NH 3 and CO 2 can be correlated with Sanderson electronegativity of the metal oxides, and the interactions of basic probe molecules with acidic surface may be described by Drago parameters. Thus, strong surface acidity can be obtained by preparing the surface possessing coordinatively unsaturated metal cations with high electronegativity while strong surface basicity may be obtained by preparing the surface possessing coordinatively unsaturated oxygen anions associated with metal cations with low electronegativity.更多还原