▎ 摘　　要

In this report, we develop an additive-free synthesis for homogeneous graphene-based heterostructures by a facile method. A room temperature semiconductor material, reduced graphene oxide (rGO) doped polyaniline (PANI) nanosheets with a 2D PANI-graphene heterostructure, has been prepared and its good sensing performance for ammonia is achieved based on the structure-property coupling effect of the heterostructure. The rGO-PANI nanosheets have the advantages of cost efficiency, environmental friendliness, reliable repeatability, good selectivity, and can be synthesized on a large scale. Besides, the sensor exhibited an excellent sensing performance toward NH3, which is manifested in linear sensibility, low limit of detection (46 ppb), and fast response (about 75 s). A wearable self-powered NH3 sensor of the early warning system is fabricated by integrating a triboelectric nanogenerator (TENG), LTC3588 conversion circuit, and the rGO-PANI nanosheets with a 2D PANI-graphene heterostructure. The sensing system can identify the specific concentration of ammonia gas through loading voltage and current changes and convert it into visual signals. The early warning system verifies the promising prospect of the practical application of the rGO-PANI nanosheet based sensor and expands the application scope of self-powered systems.