First principles study of transition metal carbide for single atom catalyst

Bipin Lamichhane, Shyam Kattel

Florida A & M University

Single-atom catalysts (SAC) are an emerging class of materials for application in catalysis. Thus a fundamental understanding of the structure composition and stability of SACs is essential to design highly performing catalysts. First-principles density functional theory (DFT) calculations were performed to study the formation and stability of Pt single atom adsorbed on transition metal carbide (TMCs)  surfaces. To this end, DFT total energy calculations were performed to compute the lattice constants and formation energies of TMCs in the rocksalt phase for TM ranging from 3d-5d series. Our calculations predicted that the DFT-calculated lattice constants are in good agreement with the experimentally determined values. In addition, the DFT results predicted favorable formation energy of many TMCs indicating the feasibility of their formation in experimental synthesis. Additional calculations were performed to obtain the surface energies of low-index TMC surfaces. Our calculations reveal that (111)  surface is more stable than (100) based on the calculated surface energy. Lastly,  Pt adsorption on TMC surfaces was computed, and the results showed that Pt binding is strongly favorable on TMC(111) surfaces indicating the thermodynamic stability of Pt-SAC configurations on TMC surfaces.