催化作用
甲醇
X射线吸收光谱法
化学
解吸
材料科学
选择性
化学工程
无机化学
铜
吸附
吸收光谱法
物理化学
有机化学
物理
工程类
量子力学
作者
Jiafeng Yu,Meng Yang,Jixin Zhang,Qingjie Ge,Anna Zimina,Tim Pruessmann,Lei Zheng,Jan‐Dierk Grunwaldt,Jian Sun
出处
期刊:ACS Catalysis
日期:2020-11-29
卷期号:10 (24): 14694-14706
被引量:129
标识
DOI:10.1021/acscatal.0c04371
摘要
Cu-based catalysts are widely employed for CO or CO2 hydrogenation into methanol. However, their catalytic performance highly depends on supports, and the real evolution of Cu species is still covered by active components. Herein, we supply a Cu/SiO2 catalyst prepared by flame spray pyrolysis (FSP), showing catalytic performance comparable to that of the active Cu/ZrO2 catalyst for methanol synthesis from CO2. It reaches 79% selectivity at a CO2 conversion of 5.2%, which is an outstanding selectivity among previously reported Cu/SiO2 catalysts, considering they are generally treated as nearly inert catalysts. In situ X-ray absorption spectroscopy (XAS) analysis shows that 5 times more Cu+ species in the FSP-Cu/SiO2 are stabilized in comparison to those in the traditional ammonia evaporation (AE) made catalyst even after reduction at 350 °C. A unique shattuckite-like precursor with a slightly distorted Cu–O–Si texture structure formed in the FSP-made catalyst is responsible for the enriched Cu+ species. Variations of intermediate formation and methanol production are found to have a good relationship with the amount of Cu+ species. According to the results of high-pressure in situ DRIFTS, we attribute this to the promotional effect of Cu+ on the stabilization of CO* intermediates, which inhibits CO desorption and facilitates further hydrogenation to CH3OH via the RWGS + CO-Hydro pathway. These results bring insights into the Cu reduction behavior and the function of Cu+ species during methanol production on Cu-based catalysts without the assistance of active supports.
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