372653 Assessing the Reliability of Calculated Catalytic Ammonia Synthesis Rates with Beef-Vdw

Monday, November 17, 2014: 10:10 AM
307 (Hilton Atlanta)
Andrew Medford1,2, Jess Wellendorff2, Aleksandra Vojvodic2, Felix Studt2, Frank Abild-Pedersen2, Thomas Bligaard2 and Jens K. Norskov2,3, (1)Chemical Engineering, Stanford University, Stanford, CA, (2)SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, Menlo Park, CA, (3)Department of Chemical Engineering, Stanford University, Stanford, CA

Using a general method for estimating the exchange-correlation uncertainty in density functional theory calculations we estimate the uncertainty on catalytic rate of ammonia synthesis over a range of transition metal catalysts. In general the estimated error is significantly reduced due to correlations in the error between various intermediates and surfaces, highlighting the need for systematic methods of error estimation. Uncertainties are shown to be a complex function of reaction condition and catalyst material, and we demonstrate that relative rates between different catalysts are better described than the absolute rates. A new approach is introduced where catalysts can be screened based on the probability that their rate will be an improvement over a given standard, rather than on the basis of absolute predicted rates. The implications and challenges of analyzing sources of uncertainty beyound exchange-correltaion energy are discussed, along with the potential opportunities for application of the probabilistic approach to other areas of computational materials design.

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See more of this Session: Applications of DFT+X in Catalysis
See more of this Group/Topical: Catalysis and Reaction Engineering Division