Precursor Design for High Density Single Pt Atom Sites on MoS₂: Enhanced Stability at Elevated Temperatures and Reduced 3D Clustering

We present a transition-metal complex containing a Pt center, large aromatic ligand, and Mo-binding terminal group, designed to maximize the dispersion of individual molecules across the 2D MoS2 substrate. The bulky organic ligand structure shows higher thermal stability than typical halides in inorganic Pt salt, such as H2PtCl6, and thus provides a large number of isolated single Pt atoms on 2D surfaces even after thermal annealing up to 900 °C. Epitaxially aligned Pt nanocrystals that are 3–5 nm in diameter are also formed upon the thermal treatment, displaying different shapes (i.e., 2D vs 3D clusters), resulting from the different atomic diffusion mechanism based on each Pt precursor. The successful generation of abundant single Pt atom sites on MoS2 surface using a large complex precursor indicates the significance of precursor design for reducing the noble metal loading in various catalysis materials.