The Kitchin Research Group

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Simulating Temperature Programmed Desorption of Oxygen on Pt(111) Using DFT Derived Coverage Dependent Desorption Barriers Spencer D. Miller, Vladimir V. Pushkarev, Andrew J. Gellman, John R. Kitchin http://link.springer.com/article/10.1007/s11244-013-0166-3 Abstract The dissociative adsorption energy of oxygen on Pt(111) is known to be coverage dependent. Simple Redhead analysis of temperature programmed desorption (TPD) experiments that assumes a coverage independent desorption barrier can lead to errors in estimated properties such as desorption barriers and adsorption energies. A simple correction is to assume a linear coverage dependence of the desorption barrier, but there is usually no formal justification given for that functional form. More advanced TPD analysis methods that are suitable for determining coverage dependent adsorption parameters are limited by their need for large amounts of high quality, low noise data. We present a method to estimate the functional form of the coverage dependent desorption barrier from density functional theory calculations for use in analysis of TPD spectra. Density functional theory was employed to calculate the coverage dependence of the adsorption energy. Simulated TPD spectra were then produced by empirically scaling the DFT based adsorption energies utilizing the Bronstead-Evans-Polyani relationship between adsorption energies and desorption barriers. The resulting simulated spectra show better agreement with the experimental spectra than spectra predicted using barriers that are either coverage-independent or simply linearly dependent on coverage. The empirically derived scaling of the desorption barriers for Pt(111) is shown to be useful in predicting the low coverage desorption barriers for oxygen desorption from other metal surfaces, which showed reasonable agreement with the reported experimental values for those other metals. The supporting information file is especially interesting because it has nearly all of the data files used in the paper embedded in it!

Copyright (C) 2013 by John Kitchin. See the License for information about copying.

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Relating the Electronic Structure and Reactivity of the 3d Transition Metal Monoxide Surfaces

Zhongnan Xu, and John R. Kitchin

We performed a series of density functional theory calculations of dissociative oxygen adsorption on fcc metals and their corresponding rocksalt monoxides to elucidate the relationship between the oxide electronic structure and its corresponding reactivity. We decomposed the dissociative adsorption energy of oxygen on an oxide surface into a sum of the adsorption energy on the metal and a change in adsorption energy caused by both expanding and oxidizing the lattice. We were able to identify the key features of the electronic structure that explains the trends in adsorption energies on 3d transition metal monoxide surfaces.

https://doi.org/10.1016/j.catcom.2013.10.028

Copyright (C) 2013 by John Kitchin. See the License for information about copying.

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The meeting took place August 18-23. See http://www.wcce9.org/ for more information.

Copyright (C) 2013 by John Kitchin. See the License for information about copying.

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Our paper "Effects of O2 and SO2 on the capture capacity of a primary-amine based polymeric CO2 sorbent" by Alexander Hallenbeck and John R. Kitchin was accepted today in Industrial & Engineering Chemistry Research. In this paper we showed that the ion exchange resin OC1065 is susceptible to poisoning by SO2, but that it can be partially chemically regenerated. It can also be damaged by long term exposure to air at elevated temperatures.

Copyright (C) 2013 by John Kitchin. See the License for information about copying.

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Our manuscript titled "Comparisons of Amine Solvents for Post-combustion CO\(_2\) Capture: A Multi-objective Analysis Approach" by Anita Lee, John Eslick, David Miller, and John Kitchin was just accepted in International Journal of Greenhouse Gas Control. In this paper we used a genetic algorithm to find pareto-optimal operating conditions of amine solvent CO2 capture systems that minimize capital cost and parasitic power cost. We compared MEA, DEA and AMP, and found that there are operating conditions where both solvents could be better than MEA.

Update: The article is online here: http://www.sciencedirect.com/science/article/pii/S1750583613002703

Copyright (C) 2013 by John Kitchin. See the License for information about copying.

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