Using MoS₂ Nanomaterials to Generate or Remove Reactive Oxygen Species: A Review

Molecular oxygen-derived free radicals and molecules that are highly reactive are generally referred to as reactive oxygen species (ROS). ROS are critical to the performance of redox-reaction-based environmental remediation approaches and at the same time are important players in the regulation of gene expression and cell signaling cascades. The irregular fluctuation of ROS can cause severe damage to the human body. Developing materials to modulate the amount of ROS is of great importance to environmental and biomedical sciences. Molybdenum disulfide (MoS2) is a prototypical transition-metal dichalcogenide that has become a star in the family of 2D materials due to its unique physicochemical properties. The band gap, catalytic activity, and piezoelectric property of MoS2 can be easily tuned by modifying its size, structure, phase, and doping with other functional materials. Some MoS2 nanomaterials are emerging as promising candidates for generating or scavenging ROS. On the one hand, MoS2 nanomaterials can effectively cause the generation of ROS via the photocatalytic reactions, photocytotoxic reactions, Fenton-like reactions, permonosulfate (PMS) activations, and piezoelectric effects. On the other hand, the exposed Mo6+/Mo4+ redox couples render MoS2 nanomaterials with antioxidant enzyme-like activity, through which ROS can be efficiently quenched. In this Review, recent advances in the applications of MoS2 for modulating ROS are summarized. Current gaps as well as possible future directions in this field are discussed.