基于探针气体吸附等温线的矿物材料表征技术:Ⅲ.表面能量非均质性

表面能量非均质性是影响固体材料表界面行为的重要属性,基于低温气体吸附等温线的分子探针方法是目前得到广泛认可的定量表征该属性的技术。本文详细介绍了这一技术的三种常用计算方法:规则化方法、密度泛函理论及微分等温线加和(DIS)法。作为应用实例,使用规则化方法和DIS方法对合成的Schwertmanite样品进行了表征,发现其表面存在三种不同的能量区域。研究结果表明,规则化方法适用于各种不同的样品,但只能给出吸附能曲线而不能精确表征表面能量区域;函数方法虽然比较精确,但表征值不能处理复杂表面;DIS方法虽能精确表征,但计算却较为繁琐。三种方法可互相补充。

Characterization Technique Ⅲ of Mineral Material Based on Probe Gas Adsorption Isotherm: Surface Energy Heterogeneity

Surface energy heterogeneity is a fundamental property of solid materials,which can influence most of their interface and surface behaviors.The molecular probe method based on low-temperature gas adsorption is a well-recognized technique to quantitatively characterize the heterogeneity.This paper has introduced three common calculation methods in detail,including regularization method,density functional theory and derivative isotherm summation(DIS).As a practical example,the lab-synthesized Schwertmanite sample has been characterized by regularization method and DIS method.It is found that there are three kinds of patches of different energetic properties on the sample surface.Finally,the applicabilities,advantages and disadvantages of the three methods have been summarized.