Barrie Patrick J
Department of Chemical Engineering, University of Cambridge, Pembroke Street, Cambridge, UKCB2 3RA.
Phys Chem Chem Phys. 2008 Mar 28;10(12):1688-96. doi: 10.1039/b717430f. Epub 2008 Feb 7.
This paper discusses some methods of analysing TPD data for samples obeying first-order desorption kinetics and proposes several improvements to existing practice. The methods apply in the case when the Arrhenius parameters A and E for each site are independent of coverage, and thus are normally suitable for the characterisation of porous solids. An improved implementation of the condensation approximation method is proposed to gain an initial estimate of the adsorption site distribution. Further, a variation of the method is proposed that can be used when A is a function of E. The initial estimate of the distribution can be used to analyse data obtained by an interrupted TPD experiment, in which heating is halted at a specified temperature. This method provides a reliable method of determining the parameter A for a peak in the distribution. Finally, regularisation procedures for obtaining physically sensible distributions from "noisy" TPD data are discussed. It is shown that a penalty function based on the square of the second derivative of the distribution is normally most suitable for analysing TPD data, at least in the case when the L-curve method is used to select the regularisation parameter.
本文讨论了一些分析服从一级脱附动力学的样品的程序升温脱附（TPD）数据的方法，并对现有做法提出了若干改进。这些方法适用于每个位点的阿累尼乌斯参数A和E与覆盖度无关的情况，因此通常适用于多孔固体的表征。提出了冷凝近似法的一种改进实现方式，以获得吸附位点分布的初始估计。此外，还提出了该方法的一种变体，可在A是E的函数时使用。分布的初始估计可用于分析通过中断TPD实验获得的数据，其中加热在指定温度下停止。该方法提供了一种确定分布中某一峰的参数A的可靠方法。最后，讨论了从“有噪声”的TPD数据中获得物理上合理分布的正则化程序。结果表明，基于分布二阶导数平方的惩罚函数通常最适合于分析TPD数据，至少在使用L曲线法选择正则化参数的情况下是如此。
