Physico-chemical properties of unusual Ga2O3 polymorphs

Article abstract of DOI:10.1007/s00706-015-1628-z

A comparative structural and spectroscopic study, combined with reactivity tests in (inverse) water-gas shift and methanol steam reforming reaction, has been performed on various Ga₂O₃ polymorphs with special focus on δ-Ga₂O₃ and ε-Ga₂O₃ with the aim of highlighting the eventual intrinsic physico-chemical properties of the latter two. Using this comparative approach, the question whether δ-Ga₂O₃ in fact is a nanocrystalline modification of ε-Ga₂O₃, a mixture of ε-Ga₂O₃ and β-Ga₂O₃, or a single polymorphic form could be answered: especially Raman spectroscopy measurements, alongside reactivity tests, indicate that δ-Ga₂O₃ exhibits lots of properties of ε-Ga₂O₃. In fact, particularly in Raman measurements it appears as a mixture of ε-Ga₂O₃ and β-Ga₂O₃.