Luminescence studies of acid-base interactions on metal oxide catalysts

Photochemistry on nonreactive and reactive (semiconductor) surfaces

“…The fraction of hydroxyl groups left on the surface can easily be monitored by fluorescent molecules like acridine or 9-anthroic acid which are excellent probes for Bronsted acidity and basicity of the surfaces. 37 In colloidal suspensions, the surface-active groups are useful in promoting adsorption via electrostatic, hydrophobic, or hydrogen bonding. The strong interactions between the surface and the adsorbed molecules often lead to aggregation effects.…”

“…Figure37. Time-resolved difference absorption spectra recorded following 308-nm laser pulse excitation of a 5 mM ZnO colloidal suspension containing (A) Ceo and (B) C70 in50/50 (v/v %) benzene-ethanol.…”

Physical Aspects of Radiation-Induced Processes on SiO2, γ-Al2O3, Zeolites, and Clays

“…As given in Table , heating γ-Al 2 O 3 increases the extent of surface CT sites. This effect is readily seen by studies of the photophysics of adsorbed arenes on γ-Al 2 O 3 . − As in the SiO 2 system, a probe molecule of established photophysics is adsorbed onto γ-Al 2 O 3 , and the resulting spectroscopy is used to interpret the surface.…”

“…Excellent examples of this technique are provided by refs −141. Here, various arenes are adsorbed to activate γ-alumina (heated at 450 °C for 4 h), β-Ga 2 O 3 , and TiO 2 (anatase).…”

Physical aspects of photochemistry and radiation chemistry of molecules adsorbed on silica, .gamma.-alumina, zeolites, and clays

“…Electron donor-acceptor complexes (EDA) of several arenes, naphthalene, phenanthrene, and biphenyl are formed with the Lewis acid sites. [169][170][171][172][173][174] The EDA complexes are characterized by new unstructured fluorescence bands located at wavelengths shifted to the red of the spectra of the physically adsorbed species.…”