Toward heterostructured transition metal hybrids with highly promoted electrochemical hydrogen evolution.

It is essential to precisely develop low-cost and sustainable electrocatalysts for the hydrogen evolution reaction. Herein, we explore a robust and controllable hydrothermal approach to synthesize defect-rich MoS nanoflakes on exfoliated MoS and WS. Such well-designed hetero-structural hybrids of MoS/exfoliated MoS and MoS/exfoliated WS exhibit dramatically promoted electrochemical activity and high stability. The as-grown MoS nanoflakes hybridized on exfoliated MoS and WS generate abundant active edge sites (rich in basal defects) and unsaturated sulfur atoms, resulting in highly enhanced electrocatalytic performance. This is expected to pave the way towards a significant improvement in transition metal dichalcogenide heterostructures as electrocatalysts.