催化作用
材料科学
X射线光电子能谱
甲醛
空间速度
热液循环
复合数
热分解
化学工程
拉曼光谱
分解
热稳定性
氧气
氧化物
复合材料
化学
选择性
有机化学
冶金
工程类
物理
光学
作者
Shuai Zhang,Haozhe Wang,Huayan Si,Xiaoqian Jia,Ziyan Wang,Qiang Li,Jing Kong,Jianbin Zhang
标识
DOI:10.1021/acsami.0c09263
摘要
A novel core-shell (ε-MnO2/CeO2)@CeO2 composite catalyst with a synergistic effect was prepared by hydrothermal reaction and thermal decomposition and its application to high-efficiency oxidation removal of formaldehyde (HCHO) was systemically investigated. The (MnCO3/CeO2)@CeO2 precursor was prepared first by the one-pot hydrothermal reaction of Mn2+ and Ce3+ solutions with a CO2-storage material (CO2SM) without any external templates or surfactants required. The thermal decomposition of the precursor afforded the core-shell (ε-MnO2/CeO2)@CeO2 composite catalyst with excellent catalytic performance. HCHO in the feed gas (180 ppm HCHO, 21% O2, N2 balanced) at a gas hourly space velocity of 100 L/(gcat h) is 100% converted over the catalyst at 80 °C. The conversion rate remains above 95% in 72 h and above 73.8% in 140 h, suggesting the strong stability of the catalyst at high gas flow rates and relatively low temperatures. The synergistic mechanism of the catalyst was explored by X-ray diffraction, Raman, Brunauer-Emmett-Teller, transmission electron microscopy, and X-ray photoelectron spectroscopy. The number of defects in the catalyst and the strength of the Mn-O bond in ε-MnO2 can be tuned by adjusting the synthesis conditions. More oxygen vacancies on the surface of CeO2 can make the synergistic effect of the catalyst stronger, which significantly improves the lattice oxygen (Olatt) activity on the surface of ε-MnO2. Our work has provided new insights into the preparation of the desired composite catalysts with excellent performances.
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