Solution-Processed Hybrid Graphene Flake/2H-MoS2 Quantum Dot Heterostructures for Efficient Electrochemical Hydrogen Evolution

• DOI: 10.1021/acs.chemmater.7b01897
• Publication Date: 2017-07-03T18:12:18Z
• Authors: Leyla Najafi; Sebastiano Bellani; Beatriz Martín-Ga...; Reinier Oropesa-N...; Antonio Esau Del ...; Mirko Prato; Iwan Moreels; Francesco Bonaccorso
• Keywords: Condensed Matter - Materials Science; Materials Science (cond-mat.mtrl-sci); FOS: Physical sciences; 02 engineering and technology; 0210 nano-technology

We designed solution-processed, flexible hybrid graphene flake/2H-MoS2 quantum dot (QD) heterostructures, showing enhanced electrocatalytic activity for the hydrogen evolution reaction (HER) with respect to their native individual components. The 2H-MoS2 QDs are produced through a scalable, environmentally friendly, one-step solvothermal approach from two-dimensional (2D) 2H-MoS2 flakes obtained by liquid phase exfoliation (LPE) of their bulk counterpart in 2-Propanol. This QDs synthesis avoids the use of high boiling point and/or toxic solvents. Graphene flakes are produced by LPE of graphite in N-Methyl-2-pyrrolidone. The electrochemical properties of 2H-MoS2 QDs and their HER-favorable chemical and electronic coupling with graphene enable to reach a current density of 10 mA/cm^2 at an overpotential of 136 mV, surpassing the performances of graphene flake/2H-MoS2 (1T-MoS2) flake heterostructures. Our approach provides a shortcut, viable and cost-effective method for enhancing the 2D materials electrocatalytic properties.<br/>31 pages, 15 figures<br/>