Characterization of plasma catalytic decomposition of methane: role of atomic O and reaction mechanism
Characterization of plasma catalytic decomposition of methane: role of atomic O and reaction mechanism
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甲烷等离子体催化分解表征：原子O的作用及反应机理
DOI：
10.1088/1361-6463/ac4728
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Oehrlein, Gottlieb S
中科院分区：
文献类型：
--
作者：
Li, Yudong;Jiang, Jingkai;Hinshelwood, Michael;Zhang, Shiqiang;Bruggeman, Peter J;Oehrlein, Gottlieb S
在这项工作中，我们研究了常压等离子体射流（APPJ）在ni - sio2 / al2o3催化剂上辅助甲烷氧化。我们通过分析气相、表面和等离子体产生的物质的相关性来评估可能的反应机制。通过改变等离子体原料气组成、等离子体功率和催化剂温度来扩大实验参数。采用实时傅里叶变换红外光谱法对反应中的气相物质进行定量分析。用分子束质谱法测量了等离子体产生的反应入射通量，采用相同的APPJ在相同条件下工作。等离子体产生的原子氧的定量通量与ch4消耗的通量以及CO和CO 2的形成有很强的相关性，这表明在所研究的条件下，O原子在ch4氧化中起重要作用。随着APPJ的整合，表观活化能降低，协同效应达到30%。我们还利用原位漫反射红外傅立叶变换光谱对催化剂表面进行了分析。表面分析表明，在25℃时，表面CO丰度反映了CH n的表面覆盖，这表明CH n作为中间物质吸附在催化剂表面，随后转化为表面CO。我们观察到在500℃时，表面CH n的吸收很少，而表面CO的吸收增加了10倍，并且CO 2的吸收更强。这表明，对于镍催化剂在500℃时，ch4解离成chn可能是我们条件下等离子体辅助ch4氧化的速率决定步骤。我们还发现，在25℃催化剂表面上，CO的振动频率从气相CO的2143 cm−1变化到2196 cm−1，而在500℃催化剂表面上，CO的频率为2188 cm−1。CO振动频率的变化可能与催化剂的氧化有关。
In this work, we investigated atmospheric pressure plasma jet (APPJ)-assisted methane oxidation over a Ni-SiO 2/Al 2 O 3 catalyst. We evaluated possible reaction mechanisms by analyzing the correlation of gas phase, surface and plasma-produced species. Plasma feed gas compositions, plasma powers, and catalyst temperatures were varied to expand the experimental parameters. Real-time Fourier-transform infrared spectroscopy was applied to quantify gas phase species from the reactions. The reactive incident fluxes generated by plasma were measured by molecular beam mass spectroscopy using an identical APPJ operating at the same conditions. A strong correlation of the quantified fluxes of plasma-produced atomic oxygen with that of CH 4 consumption, and CO and CO 2 formation implies that O atoms play an essential role in CH 4 oxidation for the investigated conditions. With the integration of APPJ, the apparent activation energy was lowered and a synergistic effect of 30% was observed. We also performed in-situ diffuse reflectance infrared Fourier-transform spectroscopy to analyze the catalyst surface. The surface analysis showed that surface CO abundance mirrored the surface coverage of CH n at 25 C. This suggests that CH n adsorbed on the catalyst surface as an intermediate species that was subsequently transformed into surface CO. We observed very little surface CH n absorbance at 500 C, while a ten-fold increase of surface CO and stronger CO 2 absorption were seen. This indicates that for a nickel catalyst at 500 C, the dissociation of CH 4 to CH n may be the rate-determining step in the plasma-assisted CH 4 oxidation for our conditions. We also found the CO vibrational frequency changes from 2143 cm− 1 for gas phase CO to 2196 cm− 1 for CO on a 25 C catalyst surface, whereas the frequency of CO on a 500 C catalyst was 2188 cm− 1. The change in CO vibrational frequency may be related to the oxidation of the catalyst.
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DOI：
10.7763/ijcte.2013.v5.815
发表时间：
2013
期刊：
International Journal of Computer Theory and Engineering
影响因子：
--
作者：
R. Phoophuangpairoj
通讯作者：
R. Phoophuangpairoj
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DOI：
10.1116/6.0000123
发表时间：
2020
期刊：
Journal of Vacuum Science and Technology
影响因子：
--
作者：
V. S. Kondeti;Yashuang Zheng;P. Luan;G. Oehrlein;P. Bruggeman
通讯作者：
P. Bruggeman
DOI：
10.1088/1361-6463/abe572
发表时间：
2021-03
期刊：
Journal of Physics D: Applied Physics
影响因子：
--
作者：
Shiqiang Zhang;G. Oehrlein
通讯作者：
Shiqiang Zhang;G. Oehrlein
影响因子：
3.4
作者：
Knoll, A. J.;Zhang, S.;Oehrlein, G. S.
通讯作者：
Oehrlein, G. S.
影响因子：
3
作者：
Zhehao Wei;Chang‐jun Liu
通讯作者：
Zhehao Wei;Chang‐jun Liu