Incorporating Au 11 nanoclusters on MoS 2 nanosheet edges for promoting the hydrogen evolution reaction at the interface.

The electrocatalytic hydrogen evolution reaction (HER) holds grip as a promising strategy to obtain renewable energy resources in the form of clean fuel - hydrogen (H 2 ). However, understanding the catalytic mechanism at the atomic level for sustainable and efficient production of hydrogen remains an arduous challenge. In this regard, atomically precise nanoclusters (NCs) with their molecule-like properties can be utilized for a better understanding of the mechanism at the catalytic interface, identification of active sites, and much more. Herein, we report a strategy to enhance the HER activity of the well-known electrocatalyst MoS 2 by the incorporation of atomically precise gold nanoclusters, Au 11 (PPh 3 ) 7 I 3 . Interestingly, Au 11 (PPh 3 ) 7 I 3 NCs were impregnated onto MoS 2 nanosheets without protecting ligands as naked Au 11 clusters which have increased atom efficiency. Different loadings of Au 11 (PPh 3 ) 7 I 3 nanoclusters on MoS 2 nanosheets revealed the superior HER activity of 2% loading of the NCs. Theoretical calculations have shown that the nanocomposite has the optimum hydrogen adsorption energy that is crucial for efficient H 2 production. Combined experimental and theoretical results provide the atomic-level understanding of the utilization of electrochemically dormant ligand-protected NCs to accelerate the HER activity of MoS 2 nanosheets.