Bulgarian Academy of Sciences 1 article published in JoVE Chemistry In situ FTIR Spectroscopy as a Tool for Investigation of Gas/Solid Interaction: Water-Enhanced CO2 Adsorption in UiO-66 Metal-Organic Framework Nikola L. Drenchev1, Kristina K. Chakarova1, Oleg V. Lagunov1, Mihail Y. Mihaylov1, Elena Z. Ivanova1, Ina Strauss2, Konstantin I. Hadjiivanov1,3 1Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 2Institute of Physical Chemistry and Electrochemistry, Leibniz Universität Hannover, 3Bulgarian Academy of Sciences The use of FTIR spectroscopy for investigation of the surface properties of polycrystalline solids is described. Preparation of sample pellets, activation procedures, characterization with probe molecules and model studies of CO2 adsorption are discussed.