SizeInduced Structural Changes in Molybdenum OxideNanoparticles

Nanosizing of metal oxide particles is a common strategy for improving materials properties, however, small particles often take structures different from the bulk material. MoO2 nanoparticles show a structure that is distinct from the bulk distorted rutile structure, and which has not yet been determined. Here, we present a model for nanostructured MoO2 obtained through detailed atomic pair distribution function analysis combined with high-resolution electron microscopy. Defects occur in the arrangement of [MoO6] octahedra, in both large (40 – 100 nm) nanoparticles, where the overall distorted rutile structure is preserved, and in small nanoparticles (< 5 nm), where a new nanostructure is formed. The study provides a piece in the puzzle of understanding the structure/properties relationship of molybdenum oxides, and further our understanding of the origin of structural changes taking place upon nanosizing in oxide materials.