郑兆宇, 徐波, 曾傲楠, 王安杰, 刘颖雅, 孙志超, 王瑶. Ni/SiO2协同DBD等离子体催化甲烷干重整性能研究[J]. 燃料化学学报(中英文). DOI: 10.19906/j.cnki.JFCT.2024022
引用本文: 郑兆宇, 徐波, 曾傲楠, 王安杰, 刘颖雅, 孙志超, 王瑶. Ni/SiO2协同DBD等离子体催化甲烷干重整性能研究[J]. 燃料化学学报(中英文). DOI: 10.19906/j.cnki.JFCT.2024022
ZHENG Zhaoyu, XU Bo, ZENG Aonan, WANG Anjie, LIU Yingya, SUN Zhichao, WANG Yao. DBD plasma-assisted dry reforming of methane over Ni/SiO2[J]. Journal of Fuel Chemistry and Technology. DOI: 10.19906/j.cnki.JFCT.2024022
Citation: ZHENG Zhaoyu, XU Bo, ZENG Aonan, WANG Anjie, LIU Yingya, SUN Zhichao, WANG Yao. DBD plasma-assisted dry reforming of methane over Ni/SiO2[J]. Journal of Fuel Chemistry and Technology. DOI: 10.19906/j.cnki.JFCT.2024022

Ni/SiO2协同DBD等离子体催化甲烷干重整性能研究

DBD plasma-assisted dry reforming of methane over Ni/SiO2

  • 摘要: 分别采用沉积沉淀法(DP)和浸渍法(IMP)制备Ni/SiO2催化剂前体,前体经H2还原得到Ni/SiO2-DP和Ni/SiO2-IMP。对所制备的催化剂进行X射线衍射、X射线光电子能谱、N2吸附-脱附、化学吸附、傅里叶变换红外、透射电镜和拉曼光谱表征,并考察其与介质阻挡放电等离子体(DBD)协同催化甲烷干重整(DRM)制合成气反应性能。研究结果表明,相较于Ni/SiO2-IMP,Ni/SiO2-DP因其较小的Ni颗粒尺寸、Ni与载体的强相互作用以及对反应物分子较强的吸附活化能力,具有更高的催化活性和稳定性。对Ni/SiO2-DP制备条件考察结果表明,H2等离子体还原(PR)的Ni/SiO2-DP-PR比程序升温还原(TPR)的Ni/SiO2-DP-TPR具有更高的催化活性。沉积沉淀时间为10 h,H2等离子体还原时间为30 min时,CH4和CO2转化率分别为72.5%和78.2%,H2和CO选择性分别为86.7%和94.2%,能量利用率为4.36 mmol/kJ。

     

    Abstract: Dry reforming of methane reaction (DRM) can convert CH4 and CO2 into syngas, which can be further utilized to produce valuable chemicals, such as hydrocarbons and liquid oxygenates. Traditionally, nickel-based catalysts have been employed for thermal catalytic DRM, which requires relatively high temperatures (>700 ℃). However, the high temperatures lead to issues such as nickel sintering, carbon deposition, and low energy efficiency, limiting the practical applications. Dielectric barrier discharge plasma (DBD) can cooperate with Ni-based catalysts, allowing the reaction to work under lower temperatures. Developing catalysts with strong synergy and high resistance to carbon coking is crucial for this technique. In this work, nickel phyllosilicate was used as a precursor to prepare highly dispersed Ni-based catalysts using H2 plasma reduction. The obtained catalysts were then used with DBD plasma to catalyze the DRM reaction. Nickel phyllosilicate was prepared using deposition-precipitation method, followed by calcination and reduction to obtain Ni/SiO2-DP. As a comparison, Ni/SiO2-IMP was prepared using the traditional impregnation method. All catalysts were characterized using XRD, XPS, N2-adsorption-desorption, H2-TPR, chemisorption, FT-IR, TEM, TG and Raman spectroscopy. The catalytic performance of DRM reaction was evaluated in a DBD reactor reactor. Ni/SiO2-DP exhibited higher activity and stability in DRM reaction compared to Ni/SiO2-IMP. Combining with the characterization results, the better performance was attributed to the enhanced interaction between Ni and SiO2 in Ni/SiO2-DP, resulting from the NiPS precursor. Such interaction led to higher dispersion and smaller particle sizes, which effectively suppressed carbon coking and improved the stability. In contrast, the weaker interaction between Ni and SiO2 in Ni/SiO2-IMP, along with larger Ni particles, resulted in rapid carbon deposition and sintering, leading to a rapid decrease in catalytic activity. Additionally, according to the CO2-TPD results, Ni/SiO2-DP has stronger CO2 adsorption capacity than Ni/SiO2-IMP, which allows an enrichment of a large amount of CO2*, CO*, and O* active oxygen species on the catalyst surface. These species can further react with CHx* and C*, slowing down the formation of carbon deposits and improve the stability of Ni/SiO2-DP. The effects of the reduction method, plasma reduction time, and precursor deposition-precipitation time of Ni/SiO2-DP were investigated. The results show that the catalytic activity of Ni/SiO2-DP-PR prepared using H2 plasma reduction (PR) is superior to that of Ni/SiO2-DP-TPR prepared using temperature programmed reduction (TPR). This is because the DBD plasma reactor contains a large number of high-energy particles, including H atoms, excited H atoms, and ionic hydrogen (H+, H2+, H3+) under discharge conditions. H2 plasma can fully reduce the catalyst precursor at low temperatures, avoiding the Ni particle aggregation during TPR. The reduction ability of H2 plasma is much higher than that of temperature programmed reduction. H2 plasma can fully reduce the precursor at low temperature, avoiding the aggregation during TPR. The optimal H2 PR time is 30 min at an input power of 25 W. The optimal deposition-precipitation time is 10 h. As the deposition-precipitation time increases, the deposited components gradually block the pores, and the specific surface area of the catalyst gradually decreases, thereby deducing the catalytic activity. Under the optimal conditions, the CH4 and CO2 conversion in the DRM reaction over Ni/SiO2-DP are 72.5% and 78.2%, respectively, with H2 and CO selectivity of 86.7% and 94.2%, respectively, and H2/CO is 0.89. The energy efficiency is 4.36 mmol/kJ.

     

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