Cyclohexanone hydrogenation to cyclohexanol on phosphomolybdate supported Pt single-atom catalyst: A density functional theory study

The single-atom catalysts (SACs) provide various novel and unique properties, as well as excellent catalytic activities due to the distinct geometrical and electronic structures. Herein, the catalytic mechanism on cyclohexanone hydrogenation catalyzed by Pt@Na₃PMA (PMA = PMo₁₂O₄₀³⁻) was investigated by using density functional theory (DFT) calculations. It is found that the most possible anchoring site for the single Pt atom is the four-fold hollow site on PMA. The bonding interaction between Pt atom and PMA comes from both ionic and covalent interaction of Pt−O bond. The calculated adsorption energy indicates that the co-adsorption of H₂ and C₆H₁₀O molecules on Pt@Na₃PMA has high thermal stability. Finally, a catalytic cycle of cyclohexanone hydrogenation by Pt@Na₃PMA was proposed, showing that the hydrogenation of carbonyl oxygen atom in cyclohexanone is the rate-determining step. For the whole reaction, Na₃PMA acts as an "electron sponge" for accepting and donating electrons. It is expected that the present work could provide the valuable perspectives for cyclohexanone hydrogenation.