Intercalation of Bi2O3/Bi2S3 nanoparticles into highly expanded MoS2 nanosheets for greatly enhanced gas sensing performance at room temperature

Synthesizing a gas sensor based on heterostructured nanomaterials (NMs) via a controllable morphology by a facile hydrothermal method is an area of frontier research. In the present work, we designed a facile strategy to synthesize a controllable morphology and composition for three component heterojunctions (MoS2-Bi2O3-Bi2S3) NMs using different hydrothermal reaction limes. The Bi2S3 easily form as an intermediate phase due to the strong interaction of the Bi2O3 with MoS2 nanosheets (NSs). The as fabricated heterojunctions MB-5 NMs exhibited a sensitive response to NOx gas (R-a/R-g = 10.7 at 50 ppm), with an ultra-fast response time of only 1 s (s) at room temperature (RT) in air. The detection limit was predicted to be as low as 50 ppb. This sensational behaviour of the sensor reveals the outstanding morphological structure and synergistic effect of the MoS2 NSs with Bi2O3 nanoparticles (NPs), which was realized by the flow of electrons across MoS2-Bi2O3-Bi2S3 interfaces through band energy alignment.