We have previously run our molecular dynamics simulations on Bescow, and would like to continue this on Dardel. The project started as a ground breaking study of large molecular catalyst at carbon-water interfaces. We have been able to simulate reactions under highly realistic conditions with salts, electric fields, solvent molecules with full dynamic treatment. We revealed a new mechanism for the oxygen-oxygen bond formation in the water splitting process. One major finding was that this mechanism was unaffected by the environment of the carbon electrode, while others are blocked. With the current allocation we will develop models for exploring more cases where this mechanism is operating, including large catalytic oligomers. Our group is the only one in the world currently studying reactions with the full complexity of the realistic system. The established distinction is becoming blurred between homogeneous catalysis, where the catalyst is dissolved in a solvent, and heterogeneous catalysis, where the catalyst is a solid reacting with gaseous or liquid reactants. Molecular catalysts attached to surfaces have advantages from both worlds, bur are notoriously difficult to model. Neither periodic or molecular DFT methods are suitable. We have therefore developed classical models based on for simulation in Gromacs and the empirical valence bond (EVB) methods to be able to simulate such catalysts under realistic conditions, taking into account the environment of the interface. We will use Gromacs and Amber and the system sizes will be significant (20k-1M atoms), which is well suited for the Beskow computing environment. The calculations will be combined with quantum chemical computations and EVB simulations, but these will be run on systems better suited for this purpose.