Low-temperature and high-selectivity butanone sensor based on porous Fe2O3 nanosheets synthesized by phoenix tree leaf template

The development of gas sensors with high selectivity to volatile ketones at low temperature has recently been a hot topic. However, the reported good response to butanone is usually achieved above 200 °C. Herein, based on the conception of biomimicry, we chose waste phoenix tree leaves (PTL) as template and simply immersed them in iron nitrate solution. Subsequently, biomorphic Fe2O3 nanosheets were controllably replicated by calcining immersed PTL precursor in air. Thereinto, Fe2O3-600 nanosheets obtained by calcining precursor at 600 °C are cross-linked by nanoparticles and have broad pore structure and large surface area. Such unique microstructure induced by bio-template imprinting not only facilitates the fast gas diffusion, but also exposes more active sites to accelerate gas adsorption and its chemical reaction with adsorbed oxygen species. In this sense, it firstly realizes the highly selective detection of Fe2O3-based material to trace butanone. At 170 °C, Fe2O3-600 sensor shows high sensing response (S = 25.8) and short response time (Tres = 5 s) to 100 ppm butanone vapor. This sensor still possesses small detection limit (100 ppb), good reversibility and anti-humidity. In addition, we explored the sensing mechanism of Fe2O3-600 nanosheets to butanone by O2-TPD, XPS and GC-MS techniques.