Tuning surface acids and electron transfer behavior by CeO₂ modification to enhance reactivity of CuCoFe-LDO...

Developing efficient catalysts with excellent low-temperature activity and poisoning resistance is critical for advancing C₃H₆-SCR technology. A series of Ce_x-CCF-LDO catalysts were prepared via a one-step co-precipitation method. The CeO₂ modification strategy significantly boosts the catalytic performance of CuCoFe-LDO. The optimized Ce_0.15-CCF-LDO delivers 88.1% NO conversion and 98.2% N₂ selectivity at 250 °C, and its NO conversion experiences a further increase after SO₂ introduction. Combined with multiple characterizations, in situ DRIFTS and DFT calculations, the performance promotion and sulfur tolerance mechanisms of CeO₂ modification were systematically clarified. CeO₂ modification markedly increases specific surface area, pore volume and oxygen vacancy concentration. The downshifted reduction temperature and doubled acid content are crucial for the improved low-temperature and overall catalytic performance. The 3d-2p-5d orbital hybridization verifies electronic interactions between Ce and transition metals, which strengthens NO and O₂ adsorption. Ce sites also exhibit lower energy barriers for O₂ dissociation and NO₂ formation. R-NCO hydrolysis serves as the critical step in the C₃H₆-SCR cycle over Ce_0.15-CCF-LDO. Ce₂(SO₄)₃ formed at Ce sites facilitates the partial oxidation of C₃H₆, yields more reactive intermediates and new species, and thus accelerates the SCR reaction. This work provides a feasible strategy for the rational design of C₃H₆-SCR catalysts.