Ultra-high response and excellent selectivity of triethylamine gas sensor based on Co3O4-ZnO porous hierarchical heterostructure

In recent years, metal oxide semiconductor nanomaterials have been found important applications in the detection of volatile organic compounds (VOCs) due to their excellent gas-sensing properties. In this study, Co3O4-ZnO porous hierarchical heterostructure nanomaterial was synthesised via the facile hydrothermal route. The sensors prepared from pristine ZnO and Co3O4-ZnO composites exhibited excellent triethylamine sensing properties. The response value of pristine ZnO to 50 ppm triethylamine was 178 at 300 °C, while the response value of Co0.5 sensor reached 2036 under the same condition, and the response value of Co0.5 sensor was 2.6 in a 500 ppb triethylamine atmosphere. Meanwhile, the selectivity of Co3O4-ZnO sample was also significantly improved compared with pristine ZnO, and the obtained sensors had excellent repeatability and long-term stability. Therefore, the Co3O4-ZnO sensor in this work had potential applications in practicable triethylamine detection. Such an exceptional triethylamine sensing performance could be sourced from its unique porous hierarchical structure and the catalytic effect of the introduced Co3O4 on the surface reaction, as well as the synergistic effect of ZnO and Co3O4. •The ZnO nanomaterial with unique porous hierarchical structure is synthesised.•The Co3O4-ZnO sensor shows ultra-high response and excellent selectivity to triethylamine.•A reference strategy for sensitising MOS material through structural and component sensitisation is provided.