Lower coordination Co3O4 mesoporous hierarchical microspheres for comprehensive sensitization of triethylamine vapor sensor

Monitoring and detecting triethylamine (TEA) vapor are essential in the organic synthesis industry. Two-dimensional Co3O4 nanosheets with large surface areas and multiple active sites are ideal for fabricating chemiresistive gas sensors. However, the face-to-face stacking owing to the high surface energy of nanosheets, would cover up the active sites, obstruct gas diffusion, raise contact resistance, which all hinder its utilization for TEA detection. Herein, the Co3O4 mesopomus nanosheets were assembled into hierarchical microspheres by adding the structure-directing agent PVP K30 and combined with a proper annealing temperature, which optimized their grain size, specific surface area, pores structure, oxygen vacancies, and the atomic ratio of Co2+ to Co3+. And these ultimately improved the detection capability of TEA. The sensor based on Co3O4 sphere-300 exhibits the highest sensor response of 34.1-100 ppm TEA and a low detection limit (0.5 ppm) at a low working temperature of 150 degrees C. The promising properties are mainly due to the combination of several advantages that facilitate simultaneous chemical and electronic sensitization. This work prepared a high-performance TEA gas sensor and verified the improvement of comprehensive sensitization on the gas-sensing performance of two-dimensional metal oxide semiconductors.

Automated summary

By assembling Co3O4 mesoporous nanosheets into hierarchical microspheres with the structure-directing agent PVP K30 and proper annealing temperature, their detection capability of TEA was optimized. The high-performance gas sensor exhibited promising properties due to simultaneous chemical and electronic sensitization, improving the overall gas-sensing performance of two-dimensional metal oxide semiconductors.