The Selection of Stable Pt Single-Atom Catalysts Supported on 3d–5d Transition Metal Carbides

The low loading of platinum (Pt) group metals (PGMs) is attractive to designing cost-effective catalysts. Among PGMs, Pt is one of the most widely used metals in catalytic applications. Single-atom catalyst (SAC) configurations allow efficient utilization of precious metals such as Pt in designing low PGM content catalysts. The thermodynamic and kinetic stability of SACs is a preliminary requirement for their long-term application in catalysis. Here, we combine density functional theory (DFT) calculations and C s -corrected scanning transmission electron microscopy (STEM) with a high-angle annular dark-field (HAADF) detector to reveal the atomic resolution and chemical contrast of Pt SAC configurations on transition metal carbide (TMC) supports. Our DFT-based thermodynamic, activation energy, and characteristic diffusion time calculations performed over a large set of Pt SAC configurations show that Pt strongly binds on polar surfaces of some common TMCs such as NbC, TaC, WC, VC, HfC, CoC, and MoC, and these Pt-bound systems show enhanced stability/durability. The theoretical predictions were further verified experimentally using a case study of Pt SAC supported on HfC. Images collected before and after a postannealing treatment and DFT calculations demonstrate the kinetic stability of Pt SACs supported on HfC. Therefore, the results from the current study provide a key guidance principle for the selection of stable Pt SACs supported on TMCs for catalytic applications.