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H2O-Enabled Reversible SO2 Resistance on Separately Dual-Functional Pd-W Sites for Low-Temperature Hydrocarbon
Chunli Ai1, Fan Dang1, Yani Wu1
1State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an 710049 Shaanxi, P. R. China.
Environmental Science & Technology
|July 10, 2026
Summary
Water can enhance catalyst resistance to sulfur dioxide (SO₂) poisoning in hydrocarbon oxidation. A novel palladium-tungsten catalyst uses water to transform SO₂ into a promoter, improving efficiency and durability.
Area of Science:
- Catalysis
- Materials Science
- Environmental Chemistry
Background:
- Sulfur dioxide (SO₂) is a major poison for noble-metal catalysts in hydrocarbon oxidation, especially in humid industrial exhaust.
- Water (H₂O) often exacerbates SO₂-induced catalyst deactivation through synergistic effects.
Purpose of the Study:
- To investigate the role of H₂O in SO₂ poisoning of hydrocarbon oxidation catalysts.
- To design a catalyst that utilizes H₂O to improve SO₂ resistance and catalytic performance.
Main Methods:
- Fabrication of a palladium-tungsten on alumina (Pd/W-Al₂O₃) catalyst with spatially separated active sites.
- Evaluation of methyl ethyl ketone (MEK) oxidation activity and SO₂ resistance under dry and humid conditions.
- Spectroscopic analysis (e.g., FTIR, XPS) and theoretical calculations (e.g., DFT) to elucidate reaction mechanisms.
Main Results:
- The Pd/W-Al₂O₃ catalyst demonstrated superior low-temperature MEK oxidation and exceptional SO₂ resistance.
- In dry conditions, SO₂ was immobilized on W sites as SO₃²⁻, protecting Pd sites.
- In humid conditions, H₂O facilitated SO₂ conversion to HSO₃⁻, which acted as a proton shuttle, enabling C-C bond cleavage and reversible catalyst recovery.
Conclusions:
- H₂O can be strategically employed to enhance SO₂ resistance in hydrocarbon oxidation catalysis.
- Spatially separated dual-functional active sites can transform SO₂ from a poison into a reaction promoter.
- This study presents a generalizable strategy for designing robust catalysts for polluted exhaust streams.
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