Confined synthesis of 2D ultrathin ZnO/Co3O4 nanomeshes heterostructure for superior triethylamine detection at low temperature

Two-dimensional (2D) ultrathin and mesoporous Co3O4 nanomeshes modified by ZnO nanocrystals (ZnO/Co3O4) was achieved via in-situ growth of ZIF-8 polyhedral particles on ultrathin ZIF-67 nanosheets, which was synthesized by a salt-template strategy followed by calcination. The ZnO/Co3O4-2 (the molar ratio of Zn/Co is 2) ultrathin nanomeshes heterostructure based sensor exhibits a much higher response (Ra/Rg) of 3.2–5 ppm triethylamine with a shorter response/recovery time of 30/55 s at a low operating temperature of 100 °C compared with pristine Co3O4 and ZnO. The enhanced gas sensing performances of ZnO/Co3O4-2 are attributed to its ultrathin mesoporous nanostructure, the presence of rich oxygen vacancy defects and unique heterojunctions at the ZnO/Co3O4 interface. This research not only provides a solid and universal design strategy for the synthesis of 2D ultrathin nanomeshes but also offers valuable guidance to optimize their gas sensing properties by heterostructure design.