Towards Understanding Catalytic processes for the Reactivity of Hydrocarbons on Rh Surface: A Quantum Chemical Study

The demand of compact and energy saving procedures for the synthesis of H2, synthesis gas and olefins from hydrocarbon fuel is expanding very rapidly as these are essentially needed in fuel cells, additive for fuel and for the cleaning and purification of flue gas. The concern is in particular to more efficient and environmentally more compatible concepts of the energy supply and reduction of pollutant emissions in mobile and stationary applications. Aliphatic hydrocarbons can be reformed efficiently through catalyst aided partial oxidation over noble metals such as rhodium and the hydrocarbons can also be converted into basic chemical substances. Due to the complex interaction between homogenous and heterogeneous reaction as well as transport processes, many experimental findings could not be interpreted till now. Only with models which are based on molecular processes, it will be possible to understand the catalysis and surface science chemistry better. Computational studies can be very useful in understanding the interaction of adsorbates with metal surfaces. These studies allow obtaining information that is difficult to measure experimentally such as adsorption energies, geometries of adsorbed molecules and activation energy of surface reactions in particular. The aim of the present work is to study the reactions relevant to partial oxidation of C1, C2 and C3 hydrocarbons in catalytic surface of rhodium by first principles calculations. DFT simulation of individual elementary step reactions is carried out. The kinetic parameters and derivative of thermodynamic data is obtained by means of the program CASTEP and VASP, which are based on periodic boundary conditions. The detailed comprehension of the surface processes enables to improve understanding of the partial oxidation catalysis occurring at Rh surface.