Concave Co3O4 octahedral mesocrystal: polymer-mediated synthesis and sensing properties

Co3O4 mesocrystals with concave octahedral structures were successfully prepared by a facile, polymer-mediated route. The Co3O4 mesocrystals are obtained from the oriented aggregation of primary nanocrystals from their six identical [100] directions. After a thorough investigation of their structure as a function of the adopted preparation parameters such as reaction time and the amount of polymer, the gas sensing performance of the Co3O4 mesocrystals was studied with formaldehyde and ethanol as probe analytes. It was found that they show high sensitivity and good response and recovery characteristics. As compared with Co3O4 powder, the Co3O4 mesocrystals exhibit 1.8-fold and 1.4-fold enhancement in gas responses to 100 ppm of formaldehyde and ethanol, respectively.