Physics and chemistry of oxidation of two-dimensional nanomaterials by molecular oxygen

The discovery of graphene has inspired extensive interest in two-dimensional (2D) materials, and has led to synthesis/growth of additional 2D materials, generally referred to as ` Beyond Graphene'. Notable among the recently discovered exotic 2D materials are group IV elemental monolayers silicene and germanene, group V elemental monolayer phosphorene, and binary monolayers, such as hexagonal boron nitride (h-BN), and molybdenum disulfide (MoS2). Environmental effect on the physical and chemical properties of these 2D materials is a fundamental issue for their practical applications in devices operating under ambient conditions, especially, exposure to air often leads to oxidation of nanomaterials with significant impact on the functional properties and performances of devices built with them. In view of its importance, we present here a review of the recent experimental and theoretical studies on the oxidation of 2D materials focusing on the relationship between the oxidation process and the energy values which can be calculated by first principles methods. The complement of experiments and theory facilitates the understanding of the underlying oxidation process in terms of cohesive energy, energy barrier to oxidation and dissociation energy of oxygen molecule for 2D materials including graphene, silicene, germanene, phosphorene, h-BN, and MoS2. (C) 2016 John Wiley & Sons, Ltd