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.