Hao Zhifei, Liu Guoquan, Wang Pengfei, Zhang Weiyu, Sun Wenming, Zheng Lirong, Guo Shaojun, Zhan Sihui
Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, People's Republic of China.
School of Materials Science and Engineering, Peking University, Beijing 100871, People's Republic of China.
Proc Natl Acad Sci U S A. 2024 Jun 11;121(24):e2311180121. doi: 10.1073/pnas.2311180121. Epub 2024 Jun 3.
As a sustainable and promising approach of removing of nitrogen oxides (NO), catalytic reduction of NO with H is highly desirable with a precise understanding to the structure-activity relationship of supported catalysts. In particular, the dynamic evolution of support at microscopic scale may play a critical role in heterogeneous catalysis, however, identifying the in situ structural change of support under working condition with atomic precision and revealing its role in catalysis is still a grand challenge. Herein, we visually capture the surface lattice expansion of WO support in Pt-WO catalyst induced by NO in the exemplified reduction of NO with H using in situ transmission electron microscopy and first reveal its important role in enhancing catalysis. We find that NO can adsorb on the oxygen vacancy sites of WO and favorably induce the reversible stretching of W-O-W bonds during the reaction, which can reduce the adsorption energy of NO on Pt centers and the energy barrier of the rate-determining step. The comprehensive studies reveal that lattice expansion of WO support can tune the catalytic performance of Pt-WO catalyst, leading to 20% catalytic activity enhancement for the exemplified reduction of NO with H. This work reveals that the lattice expansion of defective support can tune and optimize the catalytic performance at the atomic scale.
作为一种可持续且有前景的氮氧化物（NO）去除方法，用氢气催化还原NO非常值得期待，这需要精确理解负载型催化剂的结构-活性关系。特别是，载体在微观尺度上的动态演变可能在多相催化中起关键作用，然而，以原子精度识别工作条件下载体的原位结构变化并揭示其在催化中的作用仍然是一个巨大的挑战。在此，我们利用原位透射电子显微镜在以氢气还原NO的示例中直观地捕捉到了Pt-WO催化剂中WO载体因NO诱导的表面晶格膨胀，并首次揭示了其在增强催化作用中的重要作用。我们发现，NO可以吸附在WO的氧空位上，并在反应过程中有利地诱导W-O-W键的可逆拉伸，这可以降低NO在Pt中心的吸附能以及速率决定步骤的能垒。综合研究表明，WO载体的晶格膨胀可以调节Pt-WO催化剂的催化性能，使以氢气还原NO的示例催化活性提高20%。这项工作表明，缺陷载体的晶格膨胀可以在原子尺度上调节和优化催化性能。
