Atomically dispersed Ti on MnOx-Fe<sub>2</sub>O<sub>3</sub> tailors O 2p orbitals for CO oxidation and H<sub>2</sub>O/SO<sub>2</sub> resistance.

Zhao, Yongqi; Wang, Pu; Jiang, Junjie; Zhao, Ziwei; Xiu, Aorui; Liu, Xiaolong; Zhu, Tingyu · Nat Commun · 2026

basic_science · Level V

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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-Fe<sub>2</sub>O<sub>3</sub> catalyst that achieves high activity and remarkable H<sub>2</sub>O/SO<sub>2</sub> 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 SO<sub>2</sub> adsorption (from -1.96 eV to -0.19 eV) and suppress H<sub>2</sub>O competition, retaining >55% CO conversion under 10 vol% H<sub>2</sub>O and 10 ppm SO<sub>2</sub>, 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.