Graphene-supported 2D transition metal oxide heterostructures

Heterostructures of two-dimensional (2D) nanomaterials such as graphene/transition metal oxide (TMO) have recently attracted great interest due to their unique structures and superior properties that none of the individual conventional 2D nanomaterials could have. These unusual properties are due to alteration of the Fermi energy position, density of states, and work function of those heterostructures rather than their chemical components. The physical and quantum properties, the interfacial layer and the synergistic effect of each component in 2D heterostructures lead to the generation of new behavior and properties. In this review article, we are focusing on the recent progress in studying the characteristics and properties of 2D graphene/TMO heterostructures, and their significant applications in advanced energy storage and conversion devices. In this context, we firstly introduce bottom-up wet chemical approaches for the synthesis of 2D graphene/TMO heterostructures. The electron transfer, bonding chemistry and defects at the interface of these heterostructures are then discussed. Thirdly, the tunable properties of 2D graphene/TMO heterostructures and their applications in advanced energy storage and conversion devices are presented. The final section discusses the challenges and future prospects of 2D graphene/TMO heterostructures.