With the aim of preparing advanced functional materials, noble metal nanomaterials have been integrated with graphene to fully exploit and optimize their advantages. Lots of graphenebased
noble metal nanocomposites have been developed and their properties and functions in different aspects have been extensively investigated. In spite of the numerous papers published on this topic, some big challenges still exist. The shapecontrolled growth of noble metal nanocrystals on graphene remains difficult because most of the synthesized nanocrystals on graphene surfaces are spherical particles. The mechanism for the controlled growth of anisotropic noble metal architectures on a GO or rGO surface is not yet fully understood and needs further exploration. Although enhanced properties have been observed on graphene–noble metal composites, most of their applications are limited to the laboratory. Therefore, a lot of work needs to be done, in order to find a general, economic and effective method of fabricating graphene–noble metal composites for real industrial applications. Moreover, graphene-like 2D nanosheets, especially transition metal dichalcogenides, have generated significant research interest recently [131–145]. We believe that these novel 2D nanomaterials can be used as novel platforms for the construction of functional noble metal nanocomposites. As a proof of concept, recently, our group demonstrated that a solution-processable single-layer MoS2 nanosheet can be used as a new template for the epitaxial growth of Pd, Pt and Ag nanostructures at ambient conditions,
among which the Pt–MoS2 hybrid nanomaterial showed enhanced electrocatalytic activity toward the hydrogen evolution reaction [146]. More studies and developments of these novel 2D nanosheet based noble metal hybrid nanostructures are expected in the near future.