First principles study on the cadmium adsorption behaviour of MoS2 with structural defects and doping

To explore the application of MoS2 in the treatment of cadmium air pollution and Cd-containing wastewater treatment, the energy band structure and density of states of five different systems of monolayer MoS2 (without defects, with sulfur vacancies, with molybdenum vacancies, with manganese doping and with iron doping) were calculated. The contribution of the d orbital of the Mo atom near the band gap was greater than that of the p orbital of the S atom. The defect energy level was mainly due to the Mo d-state in the intrinsic DOS system and the doped atom in the doping system. Then, the adsorption capacity of these five systems for cadmium was evaluated. The adsorption capacity of MoS2 for cadmium was significantly enhanced upon introduction of defects, and Fe-doped MoS2 showed the best Cd adsorption performance among the samples. This study is expected to be helpful for understanding the energy band structure and adsorption properties of MoS2-based materials, which will aid in the exploration of environmental protection problems of MoS2 and the identification of efficient cadmium removal materials. •The relationship between the Cd partial density and the adsorption energy suggests that the s orbital of Cd plays an important role in adsorption. The Cd adsorption capacity is significantly enhanced upon formation of the defects.•Fe-doped MoS2 has an adsorption energy of −1.98 eV and the best Cd adsorption performance. This aids in the exploration of environmental protection problems of MoS2 and the identification of efficient cadmium removal materials.