A spherical spinel catalyst system based on CoFe2O4 was successfully fabricated, and the influence of the spinel and composite structure on the catalytic activity and physicochemical properties of the catalyst were systematically investigated. The Fe2O3-CoFe2O4 spherical spinel composite catalyst demonstrated significantly improved NH3‑SCR performance achieving ≥ 80% NOₓ conversion in the temperature range of 225–300 °C. Its NOx conversion was 3.03 times that of Fe2O3 and 7.45 times that of Co3O4 at 225 °C. This enhancement is attributed to the synergistic interaction between the Fe2O3 and CoFe2O4. In the inverse spinel structure of CoFe2O4, Fe3+ occupy both tetrahedral and octahedral sites, which facilitates NH3 and NOx adsorption. Meanwhile, the electronic interaction between Fe2O3 and CoFe2O4 leads to a corresponding decrease in the electron cloud density of Co, thereby enhancing their electrophilicity and further promoting the adsorption and stabilization of NO3− species. Furthermore, in situ DRIFTS results showed that coordinated NH3 and nitrate species served as the dominant reactive intermediates, following the Langmuir-Hinshelwood pathway. The reaction between bidentate nitrates and adsorbed NH3 was identified as the rate-determining step.
- Open Access
- Article
Unraveling the Mechanism and Activity of a Spherical Fe2O3-CoFe2O4 Mixed Oxide Catalyst in NH3-SCR of NOx
- Bingyi Xin,
- Ting Zhu,
- Hui Wang *,
- Zhenping Qu
Author Information
Received: 03 Apr 2026 | Revised: 03 May 2026 | Accepted: 06 May 2026 | Published: 11 May 2026
Abstract
Graphical Abstract
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