催化作用
X射线光电子能谱
氢氧化物
煅烧
无机化学
化学
水滑石
氧气
氧化物
拉曼光谱
人口
金属
铜
氧化还原
吸附
化学工程
物理化学
有机化学
工程类
物理
人口学
光学
社会学
作者
Zhiwen Li,Yifei Zhang,Qike Jiang,Liangliang Xu,Zhongkang Han,Alfons Baiker,Gao Li
出处
期刊:Langmuir
[American Chemical Society]
日期:2023-05-10
卷期号:39 (20): 6957-6963
被引量:3
标识
DOI:10.1021/acs.langmuir.2c03258
摘要
Valencies of metal species and lattice defects, such as oxygen vacancies, play a pivotal role in metal oxide-catalyzed reactions. Herein, we report a promising synthetic strategy for preparing CuO-supported CuCeOx catalysts (CuCeOx/CuO) by calcination of a hydrotalcite precursor [Cu6Ce2(OH)16]CO3·nH2O. The structural and chemical properties of catalysts were characterized by XRD, ICP-AES, TEM, TPR, NH3-TPD, XPS, Raman spectroscopy, and N2 adsorption, which revealed that the thermal pretreatment in an oxidative atmosphere caused segregation and reconstitution processes of the precursor, resulting in a mesoporous catalyst consisting of well-dispersed CuO-supported CuCeOx clusters of 1.8-3.2 nm in size with a high population of oxygen vacancies. The as-prepared catalyst shows excellent catalytic performance in the reduction of NO by CO in the absence as well as in the presence of water and oxygen. This behavior is attributed to its high oxygen defect concentration facilitating the interplay of the redox equilibria between Cu2+ and reduced copper species (Cu+/Cu0) and (Ce4+/Ce3+). The high surface population of oxygen vacancies and in situ-generated metallic copper species have been evidenced by Raman spectroscopy and X-ray photoelectron spectroscopy. The layered double hydroxide-derived CuCeOx/CuO also showed good water tolerance and long-term stability. In situ infrared spectroscopy investigations indicated that adsorbed hyponitrite species are the main reaction intermediates of the NO conversion as also corroborated by theoretical simulations.
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