(443b) Theoretical Investigation of Pt-Catalyzed Dehydrogenation of Propane to Propylene: Applying Uncertainty Analysis to Reaction Kinetics

Authors: 
Fricke, C., University of South Carolina
Heyden, A., University of South Carolina
Results of density functional theory (DFT) based-models for reaction systems are functional dependent. Changing the type of functional used for the model can often change the predictions of the model, such as the turnover frequency, reaction orders, apparent activation energy, and ultimately what active site dominates for the reaction in question. Previous work on creating a framework and methodology for quantifying uncertainty has been shown to help elucidate how certain reactions occur, and for generating a scheme for comparing different models in order to identify the most likely active site for reaction1,2.

The reaction kinetics of non-oxidative propane dehydrogenation (PDH) of propane to propylene was investigated over a series of 3 surface models, Pt(100), Pt (111), and Pt(211), using plane wave density functional theory calculations. In these calculations, we used four different functionals, which we then carried out different statistical analyses to solve a statistical forward problem (SFP) using the Quantification of Uncertainty for Estimation, Simulation and Optimization program (QUESO), in order to generate the PDH reaction’s quantities of interest, including the turnover frequency, reaction orders, and the apparent activation energy, at low conversion and low coking reaction conditions with a temperature of 633 K, based on previous experimental work3. To identify to impact of functional selection in the prior generation, we also use the energy ensembles generated by the Bayesian Error Estimation Functional with van der Waal corrections (BEEF-vdw) to generate another uncertainty model4. We created a lateral interaction model and a full hydrogen coverage model in order to replicate the reaction conditions, and generate data that may support that Pt(100) might be the active surface that non-oxdiative propane dehydrogenation occurs on in these conditions.

References

[1] J. Phys. Chem. C, 2016, 120 (19), pp 10328–10339

[2] ACS Catal., 2018, 8 (5), pp 3990–3998

[3] J Catal. 1977, 50, pp 77-88

[4] Phys. Rev. B, 2012 85, 235149