Study on Mechanism of Ionic Liquid for Methane Plasma Conversion Using Spectra Method
ZHANG Xiu-ling1, ZHOU Qian1, 2, DI Lan-bo1, YU Miao1, 2
1. College of Physical Science and Technology, Dalian University, Dalian 116622, China 2. College of Environmental and Chemical Engineering, Dalian University, Dalian 116622, China
Abstract：C6MIMBF4, C6MIMCF3COO and C6MIMHSO4 were introduced into a direct current discharge plasma system respectively for methane conversion. The kinds of active species and relative intensity of spectral peaks were detected via online spectrum diagnosis technique of optical emission spectroscopy. Mechanism of ionic liquid for methane conversion in gas-liquid plasma was investigated. The results showed that a spatially and temporally stable gas-liquid interface was obtained in ionic liquid incorporated plasma system. With introduction of ionic liquid, methane conversion and C2 hydrocarbons yields increased. The C2 hydrocarbon selectivity greatly increased when C6MIMCF3COO and C6MIMBF4 were introduced to the plasma, and decreased when C6MIMHSO4 was used. Active species like C, C2, C3, CH and H were detected in gas-liquid plasma system of methane discharge. Compared with the absence of ionic liquid in the plasma system, the relative intensity of spectral peaks of most active species increased when ionic liquid was introduced into the plasma system. 1H NMR results showed that the structure of ionic liquid kept stable during plasma discharge progress. Those indicated that ionic liquid could improve the plasma discharge intensity. At the same time, ionic liquid showed good catalytic activity in gas-liquid surface reaction.
[1] ZUO Yi-zan, ZHANG Qiang, HAN Ming-han, et al(左宜赞, 张 强, 韩明汉, 等). Chinese Journal of Catalysis(催化学报), 2009, 30(7): 624. [2] Li X S, Shi C, Xu Y, et al. Plasma Processes and Polymers, 2007, 4(1): 15. [3] LONG Jin-xing, GUO Bin, LI Xue-hui, et al(龙金星, 郭 斌, 李雪辉, 等). Acta Physico-Chimica Sinica(物理化学学报), 2011, 27(5): 995. [4] GUO Hui, WANG Jun-liang, LI Xia, et al(郭 辉, 王君良, 李 霞, 等). Chinese Journal of Catalysis(催化学报), 2011, 32(1): 162. [5] Chaurasia S K, Singh R K. Phase Transitions, 2010, 83(6): 457. [6] Li M T, Yang L, Fang S H, et al. Journal of Membrane Science, 2011, 366(1-2): 245. [7] Kaneko T, Baba K, Harada T, et al. Plasma Processes and Polymers, 2009, 6(11): 713. [8] Wei Z H, Liu C J. Materials Letters, 2011, 65(2): 353. [9] Yu M, Zhai L Y, Zhou Q, et al. Applied Catalysis A: General, 2012, 419-420: 53. [10] TONG Sheng, FAN Jie-ping, XIAO Zhu-yun, et al(童 声, 范杰平, 肖竹芸, 等). Journal of Chemical Industry and Engineering(化工学报), 2011, 62(S2): 155. [11] ZHANG Xiu-ling, LIU Zhong-fan, LI Xue-hui, et al(张秀玲, 刘中凡, 李学慧, 等). Chinese Journal of Light Scattering(光散射学报), 2004, 16 (2): 166.
