화학공학소재연구정보센터
Materials Chemistry and Physics, Vol.234, 403-410, 2019
Photoluminescence of surface chromium centers in the Cr/Al2O3 system that is active in isobutane dehydrogenation
A comprehensive study of optical and catalytic properties of highly dispersed single-phase eta-, gamma- and gamma*-Al2O3 ([Cr3+] similar to 10(-4) wt.%) powders and the related model chromia-alumina catalysts with different chromium content ([Cr3+] = 0.25, 0.5 and 1 wt%) was carried out. The catalytic characteristics (product yield, conversion and selectivity) in isobutane dehydrogenation to isobutylene were measured for all the samples under consideration. The surface Cr-s(3+) luminescence centers were detected by photoluminescence spectroscopy in all the samples. The content of Cr-s(3+) centers in the samples was estimated before and after isobutane dehydrogenation. It was shown that the amount of surface Cr-s(3+) centers correlates with isobutylene yields of the reaction. Among the studied samples, the maximum amount of Cr-s(3+) luminescence centers was found for the model 1% Cr/gamma-Al2O3 catalyst. This sample has the highest values of isobutane conversion and isobutylene yield. The comprehensive study of the Cr/Al2O3 systems made it possible to propose a method for predicting the catalytic activity of nanostructured materials using the photoluminescence detection of surface luminescence centers and their quantitative evaluation.