Chen Junlin, Shan Yulong, Sun Yu, Ding Wenqing, Xue Sen, Han Xuewang, Du Jinpeng, Yan Zidi, Yu Yunbo, He Hong
School of Rare Earths, University of Science and Technology of China, Hefei 230026, China.
Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341119, China.
Environ Sci Technol. 2023 Mar 14;57(10):4113-4121. doi: 10.1021/acs.est.2c08876. Epub 2023 Feb 22.
As a new type of catalyst with the potential for commercial application in NO removal from diesel engine exhausts, Cu-SSZ-39 catalysts must have excellent resistance to complex and harsh conditions. In this paper, the effects of phosphorus on Cu-SSZ-39 catalysts before and after hydrothermal aging treatment were investigated. Compared with fresh Cu-SSZ-39 catalysts, phosphorus poisoning significantly decreased the low-temperature NH-SCR catalytic activity. However, such activity loss was alleviated by further hydrothermal aging treatment. To reveal the reason for this interesting result, a variety of characterization techniques including NMR, H-TPR, X-ray photoelectron spectroscopy, NH-TPD, and in situ DRIFTS measurements were employed. It was found that Cu-P species produced by phosphorus poisoning decreased the redox ability of active copper species, resulting in the observed low-temperature deactivation. After hydrothermal aging treatment, however, Cu-P species partly decomposed with the formation of active CuO species and a release of active copper species. As a result, the low-temperature NH-SCR catalytic activity of Cu-SSZ-39 catalysts was recovered.
作为一种具有在柴油机尾气脱硝中商业应用潜力的新型催化剂，Cu-SSZ-39催化剂必须具备优异的耐复杂苛刻条件的能力。本文研究了磷对水热老化处理前后的Cu-SSZ-39催化剂的影响。与新鲜的Cu-SSZ-39催化剂相比，磷中毒显著降低了低温NH-SCR催化活性。然而，通过进一步的水热老化处理，这种活性损失得到了缓解。为了揭示这一有趣结果的原因，采用了多种表征技术，包括核磁共振（NMR）、氢程序升温还原（H-TPR）、X射线光电子能谱、氨程序升温脱附（NH-TPD）和原位漫反射红外傅里叶变换光谱（in situ DRIFTS）测量。研究发现，磷中毒产生的Cu-P物种降低了活性铜物种的氧化还原能力，导致了所观察到的低温失活。然而，经过水热老化处理后，Cu-P物种部分分解，形成了活性CuO物种并释放出活性铜物种。结果，Cu-SSZ-39催化剂的低温NH-SCR催化活性得以恢复。
