Structure and function correlation of supported rhenium oxide catalysts for 2-butanol dehydration and ODH of ethanol

Introduction Supported rhenium oxide catalysts have a wide range of catalytic applications, such as olefin metathesis, hydrodesulfurization, hydrogenation and NH3-SCR. Hence, the practical importance of rhenium oxide catalysts has resulted in extensive investigation of the surface structure of supported rhenium oxide catalysts. The molecular structure of supported rhenium oxides has been mainly derived from vibrational [1,2] and X-ray absorption spectroscopic [3] methods. These studies have concluded that surface rhenium oxide species possess monomer structures with C3v symmetry, consisting of three equivalent Re=O bond and one inequivalent Re-O-support bond, and that this structure is independent of support type or Re-loading. The existence of a dimer structure is still debated although no direct evidence of Re-O-Re has been obtained in either Raman or EXAFS measurements. Furthermore, it has been reported that the activity for selective oxidation of methanol [4] or ethanol [5] does not depend on the Reloading.