Abstract
Nanocrystalline cobalt oxide Co3O4 and the ZnO / Co3O4 composite were obtained by the chemical bath deposition method followed by thermal annealing. It has been shown that the growth mechanism of cobalt carbonates changes dramatically in the presence of zinc oxide particles during synthesis, as a result, the phase composition, morphology, and material properties change. The conductive layers formed from the ZnO / Co3O4 composite have an electrical resistance at room temperature that is more than three orders of magnitude lower than the resistance of the Co3O4 layers, and ZnO / Co3O4 composite gas sensors showed significantly higher gas sensitivity at room temperature than that of control cobalt oxide sensors.