Synthesis and optical properties of Co3O4 porous nanoplates converted from α-Co(OH)2 nanoplates

•Co3O4 porous nanoplates were obtained by annealing of α-Co(OH)2 nanoplates.•Co3O4 porous nanoplates exhibit a novel broad emission feature in the visible range.•PL peak likely originates from the indirect optical band gap emission.•Porous nanoplates may find new applications in visible light emitting materials.

AbstactA two-step strategy has been developed for the preparation of pure cubic phase Co3O4 porous nanoplates. Firstly, α-Co(OH)2 nanoplates were synthesized by a facile surfactant-free low-temperature solution-phase method. Secondly, the Co3O4 porous nanoplates were obtained by thermal decomposition of the as-synthesized α-Co(OH)2 nanoplates at 400 °C for 2 h in air. X-ray diffraction and Raman spectrum analyses demonstrate that the product prepared by annealing the precursor particles is composed of pure cubic phase Co3O4. Scanning electronic microscopy demonstrates that the as-prepared Co3O4 nanoparticles exhibit porous nanoplates with an ununiform morphology and a distribution of the size. Optical property investigated by photoluminescence spectrum demonstrates that the obtained Co3O4 porous nanoplates exhibit a novel broad emission feature in the visible range with a peak at about 1.68 eV, which is very close to the indirect optical band gap of 1.60 eV for Co3O4 thin film, indicating that the PL peak likely originates from the indirect optical band gap emission. These Co3O4 porous nanoplates might find new applications in visible light emitting materials.

Graphical abstractA two-step strategy has been developed for the preparation of pure cubic phase Co3O4 porous nanoplates with visible light photoluminescence.Figure optionsDownload full-size imageDownload as PowerPoint slide