Mustard gas is a kind of erosive poison with great harm and used as a chemical weapon since World War. It has suggested that the photocatalytic technology is an effective method to eliminate it. Because the small difference in molecular structure between 2-CEES and Mustard gas, and the less toxic of 2-CEES, 2-CEES is often used as a simulator to evaluate the photocatalytic activity of catalysts. In this work, symbiotic mixture of Bi2WO6 and Bi6O6(OH)3(NO3)3·1.5H2O nanosheets doped with Mo (Mo-B-B) have been synthesized by a facile hydrothermal treatment. The samples were characterized by XRD, DRS, XPS, SEM, TEM, Raman, and PL. The photocatalytic activity of the samples was evaluated by measuring the degradation of 2-CEES under visible light irradiation. The results showed that the doped Mo reduce the Eg of bare symbiotic mixture and improve the separation efficiency of photo-generated carriers that is beneficial to photocatalytic activity. The optimum amount of doped Mo is 5% that exhibits the best activity for degradation for 2-CEES. [ABSTRACT FROM AUTHOR]