Synthesis of heterogeneous ZnO/Co$_{3}$O$_{4}$ nanostructures by chemical deposition from solutions

Nanocrystalline cobalt oxide Co$_{3}$O$_{4}$ and the ZnO/Co$_{3}$O$_{4}$ 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/Co$_{3}$O$_{4}$ composite have an electrical resistance at room temperature that is more than three orders of magnitude lower than the resistance of the Co$_{3}$O$_{4}$ layers, and ZnO/Co$_{3}$O$_{4}$ composite gas sensors showed significantly higher gas sensitivity at room temperature than that of control cobalt oxide sensors.