A Zero-, Two-, and Three-dimensional Heterostructured MXene@Zn3In2S6@Polyaniline Composite for Highly Sensitive Room Temperature Ammonia Gas Sensing

Abstract

Efficient detection of ammonia (NH₃) in complex environments is challenging at room temperature. Although polyaniline (PANI) has attracted considerable attention for its applications in room-temperature gas sensing, gas sensors based on PANI materials tend to exhibit low sensitivities, slow response rates, and high detection limits. In this study, MXene microspheres were formed using the template method and two-dimensional (2D) Zn₃In₂S₆ nanosheets were grown using the solvothermal method. Subsequently, the nanosheets are modified by PANI nanoparticles via an in situ chemical oxidation polymerization protocol, and a zero-, two-, and three-dimensional (0D/2D/3D) heterostructure was successfully prepared using MXene@Zn₃In₂S₆@PANI. At room temperature and 45% relative humidity, the sensor response to 100 ppm NH₃ reached 484.28%. Notably, the response ability of the sensor was significantly enhanced with an increase in the relative humidity, reaching 1183.24% at a relative humidity of 90% (i.e., 1.54-fold greater than that at a relative humidity of 45%). This excellent moisture resistance ensures that the sensor can cope with complex environments to exhibit an excellent performance. Overall, these results suggest that MXene@Zn₃In₂S₆@PANI sensors have a promising future for use in medical and human health monitoring applications.