Metal oxide surfaces are increasingly studied as catalysts for alkane conversion, such as methane reforming. Additionally, MgO and CaO surfaces impart CO2 adsorption, which can affect the rate and mechanism of catalysis. CaO is particularly adept at CO2 adsorption, and is therefore a viable candidate for carbon-capture technologies. Previous experimental and theoretical studies of CO2 adsorption on CaO powders suggest the presence of surface carbonates due to partial agreement with the infrared (IR) absorption spectra. Well-ordered CaO(001) thin films are grown on Mo(001) and Ru(0001) substrates to explore surface morphology of CO2 adsorption via scanning tunneling microscopy (STM) and IR spectroscopy. CO2 adsorption onto CaO(001) is studied via density functional theory (DFT) with an extended-surface model as well as with the periodic electrostatic embedded cluster method (PEECM). The possibility of CaO hydroxylation from adventitious water is explored, along with molybdenum migration to the surface from the substrate. Calculated infrared peak positions and intensities, in addition to predicted peak shifts upon isotopic labeling, are compared to experiment. New insights into CO2 adsorption onto CaO single crystals have implications for surface catalysis of hydrogen production from hydrocarbons as well as advances in carbon sequestration

Adsorption of CO2 on clean CaO(001) surfaces: A joint computational-experimental investigation

251st National Meeting (2016)

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