Solution synthesis protocols for shaping mixed valent oxide crystalline particles as robust catalytic materials

Abstract

Mixed valent oxides play a very important role in catalysis, as well as in gas sensing, biomedical engineering and electrochemistry. Because many chemical and physical processes occur on heterogeneous surfaces, the surface atomic structure becomes a critical factor affecting the properties of solid inorganic materials. Therefore, shape controlled synthesis, which can promise selective exposure of specific crystallographic planes with varied Miller indices for nano- and microcrystallites of metal oxides during the synthetic process, has turned into an important research topic in multidisciplinary fields. In this review, we summarize recent progress in the solution based shape controlled synthesis of several typical mixed valent oxide nano- and microcrystallites, including TiO₂, CeO₂, FeO_x, Cu₂O, CoO_x, MnO_x, WO_x, and MoO₃. The relationship between the surface structure of some mixed valent oxide nanomaterials and their chemical reactivity in heterogeneous catalysis and photocatalysis is also concisely discussed.