2026-04-17T12:50:32Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/1636912025-11-19T20:35:45Zcom_2072_1057col_2072_478796col_2072_478917

00925njm 22002777a 4500 dc Prats Garcia, Hèctor author Gamallo Belmonte, Pablo author Sayós Ortega, Ramón author Illas i Riera, Francesc author 2020-06-02T09:21:05Z 2020-06-02T09:21:05Z 2015-12-15 2020-06-02T09:21:05Z The molecular mechanisms of the water gas shift reaction on Cu(321) have been chosen to investigate the effect of dispersion terms on the description of the energy profile and reaction rates. The present study based on periodic DFT calculations shows that including dispersion terms does not change the qualitative picture of the overall reaction, maintaining the rate determining step and the predominant route. However, the effect of dispersion is different for different adsorbates reactants, intermediates or products with a clear net effect and with no compensation of errors. Thus, in the OH+OH H2O+O process the dispersion effects imply up to three orders of magnitude in the calculated reaction rates; the formation of carboxyl is highly disfavoured when dispersion terms are explicitly included and finally, the reaction rate for CO2 production (at 463 K) through cis-COOH dissociation is enhanced by three orders of magnitude by including dispersion terms in the calculation of the energy barrier. Consequently, the inclusion of dispersion terms largely affects the overall potential energy profile and produces tremendous changes in the predicted reaction rates. Therefore, dispersion terms must be included when aiming at obtaining information from macroscopic simulations employing for instance microkinetic or kinetic Monte Carlo approaches, where these effects should be clearly shown. Teoria del funcional de densitat Catàlisi heterogènia Anàlisi funcional Density functionals Heterogeneus catalysis Functional analysis Unexpectedly large impact of van der Waals interactions on the description of heterogeneous catalyzed reactions: the water gas shift reaction on Cu(321) as a case example