Dehydroxylation of the surface of magnesium oxide by temperature programmed desorption

Near Absence of Support Effects in Toluene Hydrogenation Catalyzed by MgO-Supported Iridium Clusters

“…(However, a conflicting report (29) leads to estimates of the hydroxyl group coverages of 40, 15, and 5% of a monolayer, respectively.) Consistent with this inference that the tendency for metal aggregation is associated with the degree of surface hydroxylation, EXAFS data characterizing MgO 300 -supported iridium clusters that had been treated in H 2 at 300…”

Correlation between the Madelung field and the reactivity of the MgO low-coordinated surface sites

“…Theoretical and experimental studies have established a qualitative correlation between the chemical properties of the surface Mg-O pairs and their coordination numbers: hydrogen adsorption energy, 14 -16 hydrogen desorption temperature, [11][12][13]17 and vibrational frequencies of the OH Ϫ groups 1,18 decrease in the sequence Mg͑3C͒-O͑3C͒ϾMg͑4C͒-O͑3C͒ϾMg͑4C͒-O͑4C͒, while ionicity 14,16,19,20 and surface exciton energy 21,22 increase in the same order. The explanation of these correlations was based on the observation that surface sites with lower coordination numbers usually have lower Madelung constants.…”

Magnesium oxide as a catalyst for the dehydrogenation of n-octane

“…Structurally, MgO is an oxide with a rock-salt structure, which means that on the surface each Mg 2+ is surrounded by five O 2À ions. Magnesium oxide was reported to exhibit surface defects such as edges, corners and kinks; these surface defects were believed to play a role in the splitting of the chemical bonds of the adsorbed molecules and, thereby, may influence the catalytic performance of the MgO (Dunski et al, 1994;Klabunde et al, 1996;Knozinger et al, 2000). Generally, the anhydrous surfaces of metal oxides possess two active sites, viz.…”