Han Xinyu, Jiang Liangliang, Zhang Zeshu, Liu Kaijie, Bian Mengyao, Yuan Zhaoxu, Li Yannan, Rao Cheng, Yang Xiangguang, Zhang Yibo
Ganjiang Innovation Academy, Chinese Academy of Sciences, No. 1, Science Academy Road, Ganzhou 341000, China.
School of Rare Earths, University of Science and Technology of China, Hefei 230026, China.
Environ Sci Technol. 2025 Jun 24;59(24):12364-12377. doi: 10.1021/acs.est.5c02556. Epub 2025 Jun 9.
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.
用于氨选择性催化还原一氧化氮（NH-SCR）的铈基催化剂在实际应用中面临重大挑战，尤其是其低温活性差和易受SO中毒影响。在本研究中，创新性地将光热催化应用于MoWO/CeO催化剂上的NH-SCR反应，在低温性能和抗SO性能方面取得了显著改善。在光热条件下，即使存在250 ppm的SO，该催化剂在200℃时仍能保持NO转化率高于90%。综合表征表明，光照显著增强了催化剂表面氧空位的形成并减弱了NO吸附，这表明NH-SCR反应遵循Eley-Rideal机理，这有助于其优异的低温活性。此外，光热条件降低了SO的化学吸附强度，有效抑制了硫酸铵的形成。密度泛函理论计算进一步表明，MoWO的窄带隙促进了光照下O 2p轨道电子向Ce-O-Mo（W）界面处Ce 4f轨道的转移，导致活性位点电子富集并抑制了SO氧化。这项工作不仅为提高NH-SCR性能提供了一种新策略，也代表了低温应用中高效抗SO催化剂设计的突破性进展。
