Improving TiO₂ gas sensing selectivity to acetone and other gases via a molecular imprinting method

Various gas sensors have made considerable improvements to the quality of people's lives. However, in most cases, changing of materials is necessary to adapt to the changing of the target gas, which limits the further application of gas sensors. To meet this challenge, in this work, molecular imprinting (MI) technology is introduced. Acrylic acid is used as a functional monomer, while gas molecules, including acetone, are used as templates. The MI process with an acetone template helps improve the acetone selectivity of TiO₂ by up to 1.74-2.80 times. Moreover, it proved that other templates can increase the corresponding selectivity by at least 1.5 times by using the same matrix material. These results demonstrate the potential importance of the MI process in constructing a highly compatible gas sensor industry. Beyond this, the MI process has proved to achieve an ultrahigh specific surface area of 384.36 m² · g^-1. The optimal acetone sensor exhibits desirable comprehensive performance compared with other reports. An excellent TiO₂ based prototype acetone sensor working at 300 °C with a low detection limit of 18 ppb is obtained.