In this study, the full reaction mechanism for NO hydrogenation on silver doped Au(210) surfaces was investigated in order to clarify the experimental observations. Density functional theory (DFT) calculations were used to state the most favorable reaction paths for individual steps involved in the NO hydrogenation. From the DFT results, the activation energy barriers, rate constants and reaction energies for the individual steps were determined, which made it possible to elucidate the most favorable reaction mechanism for the global catalytic process.
View Article and Find Full Text PDFAt the core of the development of more efficient and reliable fuel cells (FCs), there are several essential chemical reactions, namely carbon monoxide (CO) oxidation. This reaction is a keystone in the cleaning of hydrogen fuel used in fuel cells due to strong poisoning by this species of the platinum catalyst used in these devices. The present work aims to provide insight regarding the activation of CO oxidation by gold or silver microfacets possessing low coordinated atoms.
View Article and Find Full Text PDFHeterogeneously catalyzed reactions take place at the catalyst surface where, depending on the conditions and process, the reacting molecules are either in the gas or liquid phase. In the latter case, computational heterogeneous catalysis studies usually neglect solvent effects. In this work, we systematically analyze how the electrostatic contribution to solvent effects influences the atomic structure of the reactants and products as well as the adsorption, activation, and reaction energy for the dissociation of water on several planar and stepped transition metal surfaces.
View Article and Find Full Text PDFThe reactivity of metallic nanotubes toward the catalysis of water dissociation, a key step in the water gas shift reaction (WGSR), was analyzed through density functional theory (DFT) calculations. Water dissociation was studied on surfaces of nanotubes based on copper, gold and platinum, and also on platinum doped copper and gold nanotubes. Gold and copper nanotubes present activities that are similar to those of their corresponding extended surfaces but, in the case of the Pt(5,3) nanotube, a significant improvement in the activity is found when compared with the extended surfaces.
View Article and Find Full Text PDFDue to the great interest that biochemical sensors constructed from graphene nanostructures have raised recently, in this work we analyse in detail the electronic factors responsible for the large affinity of biomolecular units for graphene surfaces using ab initio quantum chemical tools based on density functional theory. Both finite and periodic graphene structures have been employed in our study. Whereas the former allows the analysis of the different energy components contributing to the interaction energy separately, the periodic structure provides a more realistic calculation of the total adsorption energy in an extended graphene surface and serves to validate the results obtained using the finite model.
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