Pham Thi Kieu Ngan, Garcia Geoffrey A, Brown Joseph J
Department of Mechanical Engineering, University of Hawai`i at Mānoa, Honolulu, Hawaii 96822, USA.
Rev Sci Instrum. 2022 Jun 1;93(6):064105. doi: 10.1063/5.0073233.
The study of gas adsorption on a solid surface evaluates the affinity between sorbate gas and sorbent substrate and factors that contribute to this. This paper presents a test platform for adsorption experiments of various gases on various solid surfaces. Controlled environmental conditions enable investigations in materials surface science and increase the consistency among adsorption data. The system utilizes a quartz crystal microbalance to perform gravimetric analysis of deposition and adsorption, enabling investigation of the interaction of gaseous molecules with solid surfaces. In this study, a quartz crystal microbalance as gas adsorption detector was integrated with an environmental chamber to create a versatile tool for gas adsorption experiments on thin films. Experimental operation of this apparatus was demonstrated via acquisition of the adsorption isotherms of cyclohexane vapor on a gold surface at 55 and 70 °C. The result indicated International Union of Pure and Applied Chemistry Type II adsorption. Consequentially, application of the Brunauer-Emmett-Teller model to the isotherm data subject to predefined criteria for linear region selection yielded a surface area of the sorbent of 0.53 cm at 55 °C. From the monolayer region of the isotherms, the isosteric heat of adsorption of the cyclohexane vapor on gold was calculated to be 37 kJ mol.
对固体表面气体吸附的研究评估了被吸附气体与吸附剂基质之间的亲和力以及促成这种亲和力的因素。本文介绍了一个用于各种气体在各种固体表面上进行吸附实验的测试平台。可控的环境条件有助于开展材料表面科学方面的研究，并提高吸附数据之间的一致性。该系统利用石英晶体微天平对沉积和吸附进行重量分析，从而能够研究气态分子与固体表面之间的相互作用。在本研究中，将作为气体吸附探测器的石英晶体微天平与一个环境舱集成在一起，打造了一种用于薄膜气体吸附实验的多功能工具。通过获取环己烷蒸气在55和70°C下在金表面的吸附等温线，展示了该仪器的实验操作。结果表明属于国际纯粹与应用化学联合会的II型吸附。因此，将布鲁诺尔-埃米特-特勒模型应用于符合线性区域选择预定义标准的等温线数据，得出在55°C下吸附剂的表面积为0.53 cm²。从等温线的单层区域计算得出，环己烷蒸气在金上的等量吸附热为37 kJ/mol。
