Synthesis and properties of octahedral Co3O4 single-crystalline nanoparticles enclosed by (111) facets

Co3O4 octahedral particles, with lengths of similar to 70 nm and widths of similar to 60 nm, were hydrothermally synthesized under the assistance of triphenylphosphine (PPh3). X-ray powder diffraction (XRD) showed that the Co3O4 octahedra belong to the cubic crystal system. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) analysis indicated that these octahedral Co3O4 nanoparticles were enclosed by eight (111) facets. On the basis of crystal structure analysis and condition-dependent experiments, the unique O-terminated structure of (111) facet of Co3O4 and crystal interface restriction effect after the adsorption of [Co(OH)(a)(H2O)b(PPh3)(x-a-b)](h-a) on the surface of Co3O4 nuclei were used to explain the formation of octahedral Co3O4 nanoparticles. The catalytic activity characterization showed that the as-obtained Co3O4 octahedra can catalyze the thermal decomposition of ammonium perchlorate effectively.