High Pt-mass activity of Pt IV1/β-MnO2 surface for low-temperature oxidation of CO under O2-rich conditions

Abstract

A Pt-based CO oxidation catalyst that works even at low temperatures is desirable for industrial applications; however, its development is highly challenging because of Pt's high affinity toward CO. Here, we develop a Pt^IV single-atom/β-MnO₂ composite metal-oxide surface (Pt^IV₁/β-MnO₂). Single Pt^IV sites were stably formed on the high surface β-MnO₂ by strong interaction with Mn^IV defect sites. The resulting Pt^IV–O–Mn^IV local structures served the lattice oxygens as an oxidant to catalyze low-temperature oxidation of CO. Pt^IV₁/β-MnO₂ was highly resistant to CO poisoning because of the high-valence state of the Pt^IV single-atom sites. Aided by these geometric and electronic features, the CO oxidation was catalyzed with reaction rates of 0.676 and 0.206 mol_CO h⁻¹ g_Pt⁻¹ at 25 °C and 0 °C, respectively, under the O₂-rich conditions (O₂ : CO ratio of 66.7). These are record rates in the literature for Pt-based catalyst application for low-temperature CO oxidation under near atmospheric conditions.