Influence of Inorganic Anions on the Chemical Stability of Molybdenum Disulfide Nanosheets in the Aqueous Environment
Ting-Wei Lee, Chia-Ying Chen
Abstract
High Resolution Image Download MS PowerPoint Slide Chemical stability is closely associated with the transformations and bioavailabilities of engineered nanomaterials and is a key factor that governs broader and long-term application. With the growing utilization of molybdenum disulfide (MoS 2 ) nanosheets in water treatment and purification processes, it is crucial to evaluate the stability of MoS 2 nanosheets in aquatic environments. Nonetheless, the effects of anionic species on MoS 2 remain largely unexplored. Herein, the stability of chemically exfoliated MoS 2 nanosheets (ceMoS 2 ) was assessed in the presence of inorganic anions. The results showed that the chemical stability of ceMoS 2 was regulated by the nucleophilicities and the resultant charging effects of the anions in aquatic systems. The anions promote the dissolution of ceMoS 2 by triggering a shift in the chemical potential of the ceMoS 2 surface as a function of the anion nucleophilicity (i.e., charging effect). Fast charging with HCO 3 – and HPO 4 2– /H 2 PO 4 – was validated by a phase transition from 1T to 2H and the emergence of Mo V, and it promoted oxidative dissolution of the ceMoS 2 . Additionally, under sunlight, ceMoS 2 dissolution was accelerated by NO 3 – . These findings provide insight into the ion-induced fate of ceMoS 2 and the durability and risks of MoS 2 nanosheets in environmental applications.