高灵敏宽温区吸附热测定装置的建立

A Microcalorimetric Device for Measurement of Differential Heat of Adsorption on Surface of Solid Catalysts

描述了一个适于气 /固体系的宽温区、高灵敏的微分吸附热测定装置 .在该装置中 ,吸附放热由Setaram公司热流式微量热量计测定 ,吸附量由MKS公司电容式压力传感器测定 .此外 ,设计、制作了可在高真空和宽温区内进行吸附热测定的试样池以及对高活泼金属催化剂进行预处理的试样处理池 .用标准物质对热量计进行了标定 .为验证该装置对吸附热测定的可靠性 ,测定了H2 在Pt/SiO2 和γ Mo2 N上的吸附热 ,所得结果与文献值一致 .数据的误差分析结果表明 ,吸附热测定的相对误差在 4 %以内 .

A microcalorimetric device for the measurement of differential heat of adsorptio n on the surface of solid catalysts is described. In the device, a Setaram heat flow microcalorimeter is used to measure the heat evolved from the sample. At t he same time, an MKS Baratron capacitance manometer connected to a high v acuum system is employed to measure the amount of gas adsorbed on the sample. Be sides, a special all-metal vessel for the measurement of differential he at of adsorption on highly active catalysts, which can be operated under the con ditions of high vacuum and wide temperature range, was designed and constructed. The microcalorimeter was calibrated with standard materials. The measurement of differential heat of adsorption such as H 2 on Pt/SiO 2 and γ-Mo 2N wa s carried out. The Pt/SiO 2 sample was prepared by impregnation of silica with acetic solution of H 2PtCl 6·6H 2O and the γ-Mo 2N sample was prepare d by temperature-programmed reductive nitriding of highly pure MoO 3 in a flow of pure NH 3. The experimental results for the adsorption heat are in good agr eement with those published in the literature. The error analysis of the experim ental data shows that the relative errors for the measurement of adsorption heat are within 4%.