▎ 摘　　要

In order to effectively increase gas adsorption active sites and boost the electrical conductivity of the materials, we synthesized ultra-thin BiOCl nanosheets with the uniform dispersion on reduced graphene oxide by a facile hot-injection method for detection of the concentration of the pollutant NO2. The size of BiOCl nanosheet was controlled within 25-30 nm. TEM, EPR and XPS unveil the presence of oxygen vacancy (V-O) in the composite. The optimum BiG-3 sensor (the mass ratio of BiOCl/rGO is 1/3) exhibits a high sensitivity, elevated selectivity and remarkable long-term stability with the response (S = R-a/R-g) of 12.95-5 ppm NO2, response/recovery time of 9.3 s and 63 s, and as long as 60 days of stability at room temperature. The significant improvement in gas sensing performance of BiG-3 nanocomposite was mainly due to the highest selectivity with the higher adsorption energy of highly exposed (110) crystal planes for NO2, and a large number of oxygen vacancies providing additional active sites. Large areas of effective contact between ultra-thin BiOCl nanosheets and rGO can synergistically promote electron transport. Hence, the high sensing performance sensing material may be inspirations for actual productions.