Ab initio molecular dynamics simulation reveals the influence of entropy effect on Co@BEA zeolite-catalyzed dehydrogenation of ethane
The C-H bond activation in alkane dehydrogenation reactions is a key step in determining the reac-tion rate.To understand the impact of entropy,we performed ab initio static and molecular dynam-ics free energy simulations of ethane dehydrogenation over Co@BEA zeolite at different tempera-tures.AIMD simulations showed that a sharp decrease in free energy barrier as temperature in-creased.Our analysis of the temperature dependence of activation free energies uncovered an unu-sual entropic effect accompanying the reaction.The unique spatial structures around the Co active site at different temperatures influenced both the extent of charge transfer in the transition state and the arrangement of 3d orbital energy levels.We provided explanations consistent with the principles of thermodynamics and statistical physics.The insights gained at the atomic level have offered a fresh interpretation of the intricate long-range interplay between local chemical reactions and extensive chemical environments.
Ethane dehydrogenationC-H bond activationAb initio molecular dynamics simula-tionEntropyHeterogeneous catalysis
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