Formation of environmentally-persistent free radicals (EPFR) on α-Al2O3 clusters

Niveen W Assaf,Jomana Al-Nu'Airat,Marian W Radny,Mohammednoor Altarawneh,Bogdan Z Dlugogorski

doi:10.1039/c7ra09527a

Abstract

This study explores the role of alumina clusters assume an important role in catalyzing formation of notorious environmental persistent free radicals (EPFRs).

Highlights

Alumina oxide represents one of the most important catalytic and catalyst-support materials,[1,2,3] for chemical reactions
Heterogeneous formation of PCDD/Fs via surface-mediated coupling of chlorinated phenols were investigated on many oxide systems, including Al2O3,46,47 Co3O4,46 CuO,[48,49] TiO2 and Fe2O3.50 In our recent study,[51] we theoretically investigate the interaction of phenol molecule with the dehydrated a-Al2O3 (0001) surface
We studied the interaction of a phenol molecule with the two dehydrated alumina clusters (i.e.; cyclic and linear clusters in Fig. 3a and b)

Summary

Introduction

Alumina oxide represents one of the most important catalytic and catalyst-support materials,[1,2,3] for chemical reactions. It nds direct applications in dielectric materials, substrates for electronics, packing materials and radiation dosimeters.[4,5] Over the last two decades, the surface chemistry of alumina oxides has been a distinct research topic in catalysis chemistry Most of these studies have focused on the surface/water interface conditions, where the chemistry of the surface is greatly affected and alters its reactivity and catalytic performance.[6,7,8] The interaction of alumina surfaces with water molecules[6,9,10,11,12,13,14] results in water- and hydroxyl-covered surfaces, in which the degree of coverage is highly sensitive to temperature.[15] Heating and cooling processes can reversibly either add or remove hydroxyl groups from the surfaces, as con rmed experimentally by IR and NMR measurements.[16,17] For instance, X-ray diffraction data by Dyer et al.[18] revealed the formation of Al(OH)[3] on the g-Al2O3 surface, which disappeared a er heating to 473.15 K. X-ray photoemission experiments by Liu et al.[19] pointed out to water dissociation; most likely at surface defect sites

Methods

Results

Conclusion