Incorporating Au nanoclusters on MoS 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). 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 by the incorporation of atomically precise gold nanoclusters, Au(PPh)I. Interestingly, Au(PPh)I NCs were impregnated onto MoS nanosheets without protecting ligands as naked Au clusters which have increased atom efficiency. Different loadings of Au(PPh)I nanoclusters on MoS 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 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 nanosheets.