Chemisorption of Various Molecules on MgO

Hydrogen Experimentally no evidence for interaction with H2 has been observed at room temperature. 

Carbon Dioxide Lattice oxygen is essentially basic toward acidic molecules such as C02, forming surface CO2- (Ochs et al., 1998) see reaction (8.5)  

Water and Methanol The interaction of H20 with the (100) surface of MgO prepared by polishing and ion-bombarded single-crystal surfaces has been studied using X-ray photoelectron spectroscopy (XPS) both before and after annealing at 900 K (Onishi et al., 1987). It was observed that at room temperature water did not adsorb on the annealed surfaces. However, ion-bombarded surfaces did display features of OH-, presumably due to the creation of surface defect sites allowing water adsorption. At 200 K, both the polished and ion-bombarded surfaces showed evidence of OH- after exposure to H20, the ion-bombarded surface being covered with a monolayer of OH- (Peng and Barteau, 1990, 1991). 

Like H20, methanol (CH3OH) adsorbs only at defect sites on the (100) surface, undergoing heterolytic dissociation to methoxide (CH30) and OH- (Onishi et al., 1987). 

Carboxylic Acids Both formic and acetic acid dissociate at room temperature and below on (100) terraces giving surface hydroxide and the formate (HCOO-) and acetate (CH3COO-) species (Peng and Barteau, 1991). 

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