Spectroscopic study of the structure of chromium(VI), molybdenum(VI) and tungsten(VI) oxospecies anchored on aluminium oxide

Abstract

Diffuse reflectance in the ultraviolet–visible and Raman spectra indicate that CrVI anchored to the Al2O3 surface by ‘pulse-’ and ‘step-’ addition methods is in a monomeric form both before and after activation. Monomeric MoVI and WVI oxospecies are also the most probable products on both freshly exchanged and activated dilute samples. On more concentrated samples spectral modifications occur which can be understood without invoking polymerization effects.