Effect of Ethylene and Hydrogen Adsorption on the E.S.R. Spectra of Chromia-Alumina Catalysts

Abstract

The surface chemistry of Cr2+ and Cr3+ in chromia–alumina catalyst is investigated. Electron spin resonance studies revealed considerable changes in the behaviour of the signals ascribed to Cr3+(at g= 1.986) when exposed to H2, C2H4 and water vapour at 373 K. This work, when combined with the results from adsorption studies, allows some speculation upon the mode of adsorption of the gaseous species on the chromium ions.