UCLA

DFT-based simulations of hydride formation in the Pd/Au systems probe the thermodynamic insight of this process. The hydride formation in the 1 ML and 2 ML Pd structures was found unfavorable, with the free energies of formation being positive under the experimental conditions of interest. Nonetheless, the formation energy was reduced as the hydrogen content increased, proving the stabilization effect of hydrogen atoms. DFT calculations also revealed that the hydrogen atoms would occupy the surface sites first in the case where surface and subsurface sites were both available. The reaction pathway of EtOH dehydrogenation was investigated theoretically using DFT calculations. The rate-limiting step of the overall reaction was found to be the O-H bond cleavage step. By surveying different transition states of each bond cleavage step, the overall reaction would go through an O-H bond scission process, followed by a C-H bond scission process, to have the smallest overall barrier. However, more kinetic details of the reaction would require further microkinetic simulations.