Shunt Pt/FeO _<i>x</i> -Al ₂ O ₃ Catalysts for SO ₂ -Tolerant CO Oxidation

Sulfur, particularly SO₂, remains one of the primary poisons in catalytic systems for treating exhaust gases. Currently, the elimination of CO is still challenging in the presence of SO₂ at low temperatures (<150 °C). Herein, we introduce a strategyshunt catalysisto development of sulfur-tolerant catalysts for CO oxidation. Shunt Pt/FeO _<i>x</i> -Al₂O₃ catalysts were constructed for CO oxidation in the presence of SO₂, in which tiny Pt nanoparticles with sizes of 3-4 nm were uniformly incorporated onto binary nanohybrids composed of amorphous FeO _<i>x</i> and γ-Al₂O₃. By deliberately adjusting the Fe-to-Al ratio to be about 1:10 at the surface region of the FeO _<i>x</i> -Al₂O₃ nanohybrids, the resulting 2 wt % Pt/FeO _<i>x</i> -Al₂O₃ catalysts possessed high and persistent activity to catalyze CO oxidation (1 vol % CO) in the presence of 30 ppm of SO₂ over a wide temperature range from 30 to 140 °C. This was as a result of the Pt/FeO _<i>x</i> -Al₂O₃ catalysts being able to preferentially shunt CO to the Pt/FeO _<i>x</i> interfaces and SO₂ and its oxidation productSO₃to the Pt/Al₂O₃ interfaces, which bestowed outstanding SO₂ tolerance to the Pt/FeO _<i>x</i> interfaces for effective catalysis of CO oxidation. This work presents a practical solution to the deactivation of CO oxidation catalysts under the SO₂ atmosphere at room and industrial temperature. The key is that this shunt path can effectively alleviate the poisoning of catalytic sites caused by impurities or byproducts, thus ensuring the activity and durability of the catalyst. This is method realizes the cross-fusion of multiple catalytic sites and bionic engineering approaches.