Atomically dispersed Ti on MnOx-Fe2O3 tailors O 2p orbitals for CO oxidation and H2O/SO2 resistance

Abstract

Transition-metal oxides offer a low-cost alternative to precious metals for environmental catalysis, yet CO oxidation under humid and sulfur-laden conditions remains challenging due to rapid poisoning. Herein, we report an atomic dispersion of Ti‑decorated MnOx-Fe2O3 catalyst that achieves high activity and remarkable H2O/SO2 resistance. Atomically dispersed Ti provides electron-accepting 3d states from O 2p orbitals, which redistributes and stabilizes selected O 2p states while modifying their hybridization with neighboring Mn/Fe 3d orbitals. The localized electronic restructuring strengthens CO adsorption and facilitates lattice oxygen activation via a Mars-van Krevelen (MvK)-like mechanism, lowering the apparent activation energy to 64.59 kJ/mol. Simultaneously, Ti-O-Fe interfaces weaken SO2 adsorption (from −1.96 eV to −0.19 eV) and suppress H2O competition, retaining >55% CO conversion under 10 vol% H2O and 10 ppm SO2, far surpassing the parent oxide (<10%). The orbital tuning strategy enables scalable poison resistant catalysts for industrial emission control, reducing reliance on precious‑metal systems. Transition-metal oxides offer a low-cost alternative to precious metals for environmental catalysis, yet CO oxidation under humid and sulfur-laden conditions remains a challenge due to rapid catalyst poisoning. Here, the authors report an atomic dispersion of Ti-decorated MnOx-Fe2O3 catalyst with excellent activity and resistance to poisoning.