Shape-controlled fabrication of the porous Co3O4 nanoflower clusters for efficient catalytic oxidation of gaseous toluene

► Co3O4 nanoflower clusters were prepared by low-temperature hydrothermal method. ► PVP promoted the formation of self-assembled Co3O4 nanoflower clusters. ► The Co3O4 nanoflower showed excellent and stable catalytic oxidation properties towards toluene.