Photothermal-Enhanced Anti-SO Performance of a MoWO/CeO Catalyst in Low-Temperature NH-SCR.

Cerium-based catalysts for the selective catalytic reduction of NO with ammonia (NH-SCR) face significant challenges in practical applications, particularly their poor low-temperature activity and susceptibility to SO poisoning. In this study, photothermal catalysis was innovatively applied to the NH-SCR reaction over MoWO/CeO catalysts, achieving remarkable improvements in the low-temperature performance and SO resistance. Under photothermal conditions, the catalyst maintained NO conversion above 90% at 200 °C, even in the presence of 250 ppm of SO. Comprehensive characterization revealed that light irradiation significantly enhanced the formation of oxygen vacancies on the catalyst surface and weakened NO adsorption, indicating that the NH-SCR reaction follows the Eley-Rideal mechanism, which contributes to its excellent low-temperature activity. Moreover, photothermal conditions reduced the chemical adsorption intensity of SO, effectively inhibiting the formation of ammonium sulfate. Density functional theory calculations further demonstrated that the narrow band gap of MoWO promotes electron transfer from the O 2p orbital to the Ce 4f orbital at the Ce-O-Mo(W) interface under light, leading to electron enrichment at active sites and suppression of SO oxidation. This work not only provides a novel strategy for enhancing the NH-SCR performance but also represents a groundbreaking advancement in the design of highly efficient, SO-resistant catalysts for low-temperature applications.