This work describes surface science studies, performed mainly in ultra high vacuum (UHV), aiming at the understanding of environmentally relevant processes including mixed metal-oxide formation, hydroxylation of surfaces and adsorption of organic molecules on oxide surfaces. Well-defined thin oxide film model systems were created in UHV and investigated by x-ray photoelectron spectroscopy (XPS), thermal desorption spectroscopy (TDS) and low energy electron diffraction (LEED). Additional data derived from scanning tunneling microscopy (STM), infrared reflection absorption spectroscopy (IRAS) and density functional theory (DFT) were provided by collaborators. The results of this work contribute to a better understanding of the interaction of surfaces with their direct environment and the influence of oxygen, water and organic molecules on the surface structure. The thesis contains three experimental parts.In the first part, the focus lies on the formation of two-dimensional ternary tungstate layers, namely FeWOX layers, supported by Pt(111). Two different two-dimensional phases, the well ordered (2x2)-FeWO3 and the (6x6)-Fe6W8O21 phase were found by applying a solid state reaction between monolayer FeO(111) and (WO3)3 clusters. First reactivity studies were carried out on the (2x2) phase, which are the basis for more systematic investigations in the future.The second part deals with a bilayer SiO2/Ru(0001) film and its possible functionalization by thermal and electron-assisted hydroxylation. The emerging hydroxyl groups could act as anchoring sites for atoms/molecules, which was investigated by using palladium atoms/particles. It is shown how electron-assisted hydroxylation significantly increased the number of silanols (Si-OH) and weakly bound water molecules on the surface. In the end, this molecular bound water was identified to be responsible for pore blocking on the silica film, which enabled the creation of controllable porosity states for Pd atoms resulting in either surface Pd clusters or Pd atoms at the Ru interface.At last, the adsorption of the organic molecules 1,2-dihydroxybenzene (catechol) and 4-aminophthalic acid (4-APA) was studied on bare Pt(111), FeO(111) and Fe3O4(111). The thermal stability in UHV as well as the molecule stability in ambient conditions were investigated, leading to the observation of different adsorption behaviors in dependence of molecule and substrate. It is shown, that 4-APA is in general much more strongly bound to the substrates as catechol. Both molecules bind to the substrate and the interfacially bound species decompose, except catechol on FeO(111), before desorption. The stability of the molecules is lowest on Pt(111) and highest on Fe3O4(111).