Facile synthesis of bimodal mesoporous spinel Co3O4 nanomaterials and their structural properties

Mesoporous spinel Co3O4 nanomaterials have been prepared effectively via simple solid state mixing of nitrate precursor with various modifiers, including citric acid, urea, glucose and sucrose, followed by thermal treatment. The as-synthesised spinel Co3O4 materials showed high porosity, and the particles were finely crystallised in the nanorange. The different organic modifiers used in the synthetic method played a major role in the development of various porous morphologies. Different analytical techniques were used to study the material's structural and textural features. X-ray diffraction analysis revealed the cubic phase purity of the cobalt oxide nanomaterials. The monoclinic and face centred cubic phases of CoO were detected in the glucose- and sucrose-assisted samples. The scanning electron microscopic images confirmed the surface porosity of the spinels with various morphologies. Macro-porous morphology with large holes was noted in the citric acid-assisted sample. The transmission electron microscopy images indicated that the bimodal mesoporosity of the spinels started from the deep bulk to the surface. BET-BJH analysis indicated that the surface area and pore parameters of the spinels were related to the type of modifier. Moreover, a high surface area was noted for the citric acid-aided Co3O4 (29 m(2)/g). The bimodal pore-size distributions were clearly confirmed from the TEM and the BJH-porosity measurements. (C) 2013 Elsevier Ltd. All rights reserved.