NITROXYL RADICALS AS SPIN PROBES FOR THE STUDY OF LEWIS AND BROENSTED ACID SITES OF OXIDE CATALYSTS

摘要

The use of series of nitroxyl radicals possessing different stability with regard to the protonation has permitted us to develop a simple experimental technique for measurement of the quantity of the Lewis acid site-strong Bronsted acid site pairs and for the estimation of the strength of such acid sites. Lewis acid site acts as the site of the radical adsorption while neighboring Bronsted acid site accounts for the radical protonation and the following loss of paramagnetism.