Vertically conductive MoS2 pyramids with a high density of active edge sites for efficient hydrogen evolution

Molybdenum disulfide (MoS2) has attracted tremendous interest as a noble metal-free catalyst for the hydrogen evolution reaction (HER). However, its electrocatalytic performance is currently limited by the density of active sites and poor electrical transport to these sites. Here, we report vertically conductive multi-layered MoS2 pyramids with a high density of active edge sites. Conductive atomic force microscopy (c-AFM) reveals the thickness-independent vertical conductivity for the spiral MoS2 pyramids. And the active edge sites on the MoS2 pyramids are confirmed through Cu electrochemical deposition. Due to the thickness-independent vertical conductivity and high density of active edge sites, the MoS2 pyramids demonstrate a highly enhanced HER performance compared to that of MoS2 triangular flakes. Additionally, the multi-layered spiral pyramid structure can be extended to other transition metal dichalcogenides, and may open up various possibilities for optoelectronic and catalytic nanodevices.