Physico-chemical Properties Of Ga₂O₃ Polymorphs

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 s-Ga₂O₃ with the aim of highlighting the eventual intrinsic physico-chemical properties of the latter two.Using this comparative approach,the question whether 8-Ga₂O₃ in fact is a nanocrystalline modification of ε-Ga₂O₃,a mixture of s-Ga₂O₃ and β-Ga₂O₃ or a single polymorphic form could be answered:Especially Raman and Infra-red 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 s-Ga₂O₃ and β-Ga₂O₃.The outlined results in turn reveal the importance of a focused approach by combining different methods providing complementary information to resolve structural issues.