One-step synthesis and the enhanced trimethylamine sensing properties of Co3O4/SnO2 flower-like structures

Co3O4/SnO2 flower-like structures were prepared via an one-step hydrothermal technique. Pure SnO2 and Co3O4 were used as reference, which were synthesized in the same condition by the hydrothermal technique. The products were characterized by field emission scanning electron microscopy (FESEM), X-ray diffractometer (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) nitrogen adsorption-desorption. It is revealed that p-n heterojunctions was formed. The TMA gas sensing measurement were investigated. The sensor made of 5 mol% Co3O4/SnO2 flower-like structures exhibited response value of 9.3 to 5 ppm TMA at 175 degrees C, which is about 2.9 times higher than pure SnO2 sensor and 7.2 times higher than pure Co3O4 sensor at same temperature, respectively. In addition, this sensor also showed rapid response and recovery times to 5 ppm TMA (19 s and 29 s, respectively), good reproducibility and stability, lower detecting limit level (1 ppm), and good selectivity at 175 degrees C. The improved TMA sensing performance might be attributed to forming p-n heterojunctions at interface and Co3O4 catalytic actions. Our works offer a synthesis method for fabricating Co3O4/SnO2 flower-like structures. Moreover, the hierarchical Co3O4/SnO2 p-n heterojunctions could be a promising candidate for TMA gas detection in the future.