Metals surfaces form a group of effective catalysts for the reaction of small molecules such as hydrogen (H2). In order to improve the predictive power of theory with respect to the catalytic... Show moreMetals surfaces form a group of effective catalysts for the reaction of small molecules such as hydrogen (H2). In order to improve the predictive power of theory with respect to the catalytic activity of small molecules reacting at metal surfaces, the way in which metal surfaces modify the potential energy of molecules needs to be understood at a fundamental level. Currently density functional theory (DFT) is the only electronic structure method that is accurate enough to achieve chemical accuracy while being cheap enough to make large comparative studies feasible. The work in this thesis is concerned with the creation of highly accurate density functionals that can give a simultaneously good description of the metal surface, the molecule, and the molecule interacting with the metal surface, as well as the description and simulation of supersonic molecular beam experiments and associative desorption experiments needed to validate the obtained results. Show less
This research was about to better understanding of heterogeneous catalyzed processes which would help to design better and more efficient catalysts but it is hard to achieve because of their high... Show moreThis research was about to better understanding of heterogeneous catalyzed processes which would help to design better and more efficient catalysts but it is hard to achieve because of their high level of complexity. In this way, we compared molecular beam experiments with molecular dynamics simulations to improve over the theoretical method used, called density functional theory (DFT), to achieve chemical accuracy (i.e., errors smaller than 1 kcal/mol) for the reaction studied. Show less
The research presented in this thesis makes use of small molecules (as H2 , D2 and O2 ) on well-defined single crystal surfaces (flat Pt(111), flat Cu(211) and curved Pt(111)) to elucidate the... Show moreThe research presented in this thesis makes use of small molecules (as H2 , D2 and O2 ) on well-defined single crystal surfaces (flat Pt(111), flat Cu(211) and curved Pt(111)) to elucidate the role of surface structure and degrees of freedom in the reactant in specific surface reactions. For D2 on Pt(111), we find at most a very weak signature of geometric corrugation at large polar angles. For D2 on Cu, we find an anomalous reduced dissociative sticking probability for the stepped Cu(211) surface compared to Cu(111). For hydrogen on curved Pt(111), the HD formation increases linearly with the step density at low incident energy. A surface reconstruction on curved Pt(111) surface is observed on both A- and B-step side when the crystal is annealed at 1200 K. For O2 on curved Pt(111), at low incident energy, steps dominate reactivity by providing an indirect dynamical trapping mechanism. At higher impact energy, a direct chemisorption mechanism dominates. The step facet favors molecules impacting with their internuclear axis parallel to its surface. Show less
Cao, K.; Lent, R. van; Kleyn, A.W.; Juurlink, L.B.F. 2018