New insight into the inevitable oxidation-dissolution behavior of MoS2 at humid environments: Unexpected persistent generation of hydroxyl radicals

Abstract

The long-term persistence of transition metal dichalcogenide (TMD) gets severely weakened at humid environments, which is key issue to solve in application. However, previous studies about TMD oxidation mainly focused under light irradiation, while lack of exploration at dark environments. Herein, we filled the gap in research of the oxidation and dissolution behaviors of TMD, represented by molybdenum disulfide (MoS2). under dark condition. The results demonstrate that water and oxygen could react produce hydroxyl radicals (•OH) on MoS2 interface, a critical intermedia for MoS2 oxidation and dissolution. Ab-initio molecular dynamics (AIMD) simulations present detailed formation process of •OH over MoS2 surface, and spin-polarized density functional theory (DFT) calculations confirm its generation. While, under basic conditions, AIMD and DFT calculations demonstrated the generation of H2O2 at MoS2 hydroxylated surface. This work will assist in understanding of MoS2 oxidation and dissolution behavior, and provide references for the investigation of long-term stability of TMDs.