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

Abstract

Abstact A two-step strategy has been developed for the preparation of pure cubic phase Co 3 O 4 porous nanoplates. Firstly, α -Co(OH) 2 nanoplates were synthesized by a facile surfactant-free low-temperature solution-phase method. Secondly, the Co 3 O 4 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 Co 3 O 4 . Scanning electronic microscopy demonstrates that the as-prepared Co 3 O 4 nanoparticles exhibit porous nanoplates with an ununiform morphology and a distribution of the size. Optical property investigated by photoluminescence spectrum demonstrates that the obtained Co 3 O 4 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 Co 3 O 4 thin film, indicating that the PL peak likely originates from the indirect optical band gap emission. These Co 3 O 4 porous nanoplates might find new applications in visible light emitting materials.