Enhanced NH3 sensing performance of polyaniline via a facile morphology modification strategy

The synthesis of polyaniline (PANI) composites is an effective method to improve the ammonia (NH3) gas sensing performance of PANI, and it is of great significance to develop a simple method to prepare PANI composites. Herein, the PANI/halloysite nanotubes (PANI/HNTs) composite was prepared via a simple in-situ polymerization method. Morphology characterization results show that the HNTs are covered by PANI to form a porous three-dimensional structure. Especially, the specific surface areas of the PANI and PANI/HNTs are 15.892 and 25.899 m2/g, respectively, and the specific surface area of PANI has been greatly improved (1.63 times). Gas sensing properties test results show that the PANI/HNTs sensor exhibits larger response (1.60 times) and shorter response/recovery times (0.93/0.6 times) than that of the PANI sensor to 10 ppm NH3 (25 °C, 50% relative humidity). In addition, the PANI/HNTs sensor exhibits low detection limit of 10 ppb NH3 and excellent selectivity. The enhanced NH3 sensing performance of PANI can be attributed to the unique hollow structure and large specific surface area of HNTs. In this work, a simple method is proposed to improve the NH3 sensing performance of PANI only by morphology modification. Meanwhile, it provides an idea for the application of HNTs in the field of gas sensors.