Synergy of S-vacancy and heterostructure in BiOCl/Bi2S3−x boosting room-temperature NO2 sensing

The special physicochemical properties of Bi2S3 nanomaterial endow it to be exceptional NO2 sensing properties. However, sensors based on pure Bi2S3 cannot detect trace NO2 at room temperature effectively due to the scanty active sites and poor charge transfer efficiency. Herein, vacancy defect and heterostructure engineering are rationally integrated to explore BiOCl/Bi2S3−x heterostructure with rich S vacancies to enhance NO2 sensing performance. The optimized sensor based on S-vacancy-rich BiOCl/Bi2S3−x heterostructure exhibited a high response value (Rg/Ra = 29.1) to 1 ppm NO2 at room temperature, which was about 17 times compared to the pristine Bi2S3. Meanwhile, the BiOCl/Bi2S3−x sensor also exhibited a short response time (36 s) towards 1 ppm NO2 and a low theoretical detection limit (2 ppb). The superior response value of S-vacancy-rich BiOCl/Bi2S3−x heterostructures was ascribed to the improved electron migration at the heterointerface and the additional exposed active sites caused by the S vacancies in Bi2S3−x. Additionally, the sensors based on S-vacancy-rich BiOCl/Bi2S3−x heterostructures showed good long-term stability, outstanding selectivity, and good flexibility. This study offers an effective method for synergistically engineering defect and heterostructure to enhance gas sensing properties at room temperature. [Display omitted] •S-vacancy-rich BiOCl/Bi2S3−x heterostructure is prepared by a hydrothermal process.•The BiOCl/Bi2S3−x sensor shows ultrahigh response value (Rg/Ra = 29.1) to 1 ppm NO2.•Enhanced sensing response is due to the synergy of S vacancies and heterostructures.