Active Electronic States of Silver Catalysts for Methanol Selective Oxidation
Applied Catalysis A: General
, E-ISSN: 1873-3875
||Formaldehyde, IR spectroscopy, Methanol oxidation, Silver
Tomsk State Academy ofCivil Engineering, TISI, Solyanaya sq., 2, Tomsk, 634003, Russia
Boreskov Institute ofCatalysis, Lavrentyev av., 5, Novosibirsk, 630090, Russia
The results of investigations of the electronic and catalytic properties of silver catalysts by IR spectroscopy of adsorbed carbon monoxide, diffuse reflectance electron spectroscopy, electron microscopy and catalytic testing have been combined and examined. Of those metals of which the configuration of the valence electronic shell is dns1 (Cu, Ag, Au, Pt, Pd, Rh, Ru), silver has the highest effective charge as M+ cation due to the most resistant d-electron shell. Supports and modifying additions of metal oxides have a pronounced effect on the electronic state and red-ox properties of silver as a result of donor-accepter interaction of the metal oxide. The factors that stabilize the ionic state of silver and increase its effective charge seem to improve the catalytic properties of silver in methanol oxidation. A hypothesis on the active electronic state of silver in this process — Ag+ cations with maximum effective charge — is suggested based on comparison of spectroscopic and catalytic data.