This proposal deals with two broad scientific projects: static quantum-mechanical calculations and various types of molecular dynamics (MD) simulations of (A) extended metal and metal oxide surfaces and nanoparticles (NPs), and (B) the structure, interactions and dynamics of aqueous systems, including solvated ions or NPs. The calculations are made to discover the atomic-level chemical and physical processes involved in heterogeneous catalysis, electrochemistry, and toxicological effects of NPs. These processes are complicated and poses several scientific and modelling challenges. For example, the surfaces and interfaces involved are very complex, and imperfect leading to large chemical systems. Interfacing NPs with liquid leads to long simulation times, not only to reach equilibrium, but also to collect sufficient statistics.