Phosphomolybdic acid supported single-metal-atom catalysis in CO oxidation: first-principles calculations

Abstract

CO oxidation on phosphomolybdic acid (H₃PMo₁₂O₄₀, PMA) supported single-metal atom (M = Pt, Au, Co, Cu, Fe, Ir, Ni, Os, Pd, Ag, Rh, and Ru) (M-PMA) catalysts is studied by density-functional-theory (DFT) calculations. Adsorption of CO and O₂ on M-PMA is investigated. Based on electronic structure analysis, O₂ is activated by the single-metal-atom active center. The Langmuir–Hinshelwood mechanism is systematically explored for CO oxidation on M-PMA, and it is found that M-PMAs have high reactivity toward CO oxidation. The Mars–van Krevelen mechanism is also investigated and it is shown to be less likely to be responsible. Our DFT findings will provide useful insight for designing stable, highly active heteropolyacid-supported single-metal-atom catalysts.