Synthesis and properties of octahedral Co3O4 single-crystalline nanoparticles enclosed by (111) facets†
Abstract
Co3O4 octahedral particles, with lengths of ~70 nm and widths of ~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.