Edge-rich MoS2 grown on edge-oriented three-dimensional graphene glass for high-performance hydrogen evolution

Abstract

The more exposures of the photocatalytically active sites are one of the essential elements to achieve high photocatalytic efficiency. Through the architecture designs, we have proposed an edge-rich MoS2 nanoarray grown on an edge-oriented three-dimensional (3D) graphene (termed as the 3D-graphene/E-MoS2) via chemical vapor deposition. Unlike the two-dimensional (2D) graphene, the highly conductive and transparent 3D graphene film has been grown at oblique angles on glass (i.e., a graphene glass), providing the large exposed surface area for the loading of more photocatalysts. Then, the abundant photocatalytically active sites can be achieved in the subsequently deposited edge-rich MoS2 nanoarrays, which are significantly beneficial for photocatalytic hydrogen production. The theoretical and experimental studies have revealed the new finding in the substantial improvements of both optical and electrical properties based on the geometrically designed 3D-graphene/E-MoS2 structures. Optically, the excellent light absorption (wavelength range: 300–800 nm) is observed, which is attributed to the favorable energy band for the efficient charge transfer between the electronically interconnected graphene and MoS2, and orientation of the MoS2 crystal face array. Electrically, the edge-rich MoS2 grown on the edge-oriented 3D graphene glass can achieve the optimized charge transport along the 2D vector plane from MoS2 layers to graphene. Consequently, the new hybrid nanostructures exhibit excellent performance as an effective photocatalyst for hydrogen generation from photocatalytic water splitting. The measured hydrogen evolution rate (2232.7 μmol/g/h) under white-light illumination is one of the highest among those photocatalysts reported to date.