| In view of its high surface area to mass ratio (2600 m2/g), superior charge-carrier mobility (2 × 105 cm2/V · s) and excellent thermal conductivity of (4.84~5.30) × 103 W/m·K, graphene has been considered an ideal substrate for growing and anchoring various metal and metal oxide nanocrystals (NCs) to form high-performance nano-composites. The manufacturing of such graphene hybrids would require not only that graphene sheets be produced inexpensively and in large quantities, but also that the attached metal/metal oxide NCs be incorporated and homogeneously distributed on the graphene surface. Up to now, many approaches have been developed to decorate graphene with metal/metal oxide NCs. However most of these techniques failed to provide consistent results, lead to graphene hybrid devices with poor performance and stability, and are cost prohibitive for large-scale production. In this report, we present a novel nanomanufacturing process which is simple, reliable, safe, and cost-effective and environmentally benign, capable of fabricating high quality graphene-based metal and metal oxide hybrids that are suitable for use in a variety of applications. During the manufacturing we were able to eliminate the surfactants and stabilizers using our Thermal Expansion--Liquid Exfoliation--Solvothermal Reaction (TELES) process. This allows the interface between the graphene and the metal or metal oxide NCs to remain very clean—improving material properties and stabilities—while eliminating a potential environmental hazard. Our study suggests that these nanomaterials would be scaled to the industrial level and could be used to produce high-performance graphene hybrid devices. Further more, we have identified three categories of interest within the clean energy category that can be addressed through the use of graphene based metal and metal oxides hybrids: energy storage (supercapacitors), energy conversion (fuel cells), and energy production (water splitting).
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