Core level shifts as indicators of Cr chemistry on hydroxylated α-Al₂O₃(0001): a combined photoemission and first-principles study

Abstract

The Cr/$\alpha$-Al$_2$O$_3$(0001) interface has been explored by X-ray photoemission spectroscopy, X-ray absorption spectroscopy (XAS) and {\it ab initio} first-principle calculations of core level shifts including final state effects. After an...

Transition from monolayer-thick 2D to 3D nano-clusters on α-Al2O3(0001)

“…Instead, it has been chosen herein to explore Ag/α-Al 2 O 3 (0001) by Extended X-ray Absorption Fine Structure (EXAFS). The authors have proved the flexibility and the reliability of this technique for studies on oxide-supported Ag, 47–49 Na 50–52 and Cr, 8,9 and on Ag-supported MgO nanoparticles, 53 with a relevance even increased in the recent years by the systematic support of atomistic calculations. 8,9,49,53 As a local probe, EXAFS has several crucial advantages over imaging and diffraction experiments as it allows the in situ exploration of deposit conformation and environment for surface coverages as small as a tenth of a monolayer in the absence of long-range order.…”

“…The authors have proved the flexibility and the reliability of this technique for studies on oxide-supported Ag, 47–49 Na 50–52 and Cr, 8,9 and on Ag-supported MgO nanoparticles, 53 with a relevance even increased in the recent years by the systematic support of atomistic calculations. 8,9,49,53 As a local probe, EXAFS has several crucial advantages over imaging and diffraction experiments as it allows the in situ exploration of deposit conformation and environment for surface coverages as small as a tenth of a monolayer in the absence of long-range order. As regards the chosen Ag/α-Al 2 O 3 (0001) system, it is likely the metal/alumina interface which has concentrated the most important theoretical research efforts owing to its applicative interest in catalysis in particular for the major reaction of ethylene epoxidation.…”

“…These systems are of considerable interest as the α-Al 2 O 3 (0001) surface is the second most studied oxide surface after the (110) one of rutile TiO 2 . 4 Since it is not reduced in contact with most transition metals, 5–9 this surface offers a vast playground to explore sharp interface properties. Its attractiveness is increased by the countless applications of metal/alumina interfaces to catalysis, 10–14 microelectronics 6 and functional coatings.…”