催化学报 ›› 2025, Vol. 71: 220-233.DOI: 10.1016/S1872-2067(24)60267-6

• 论文 • 上一篇    下一篇

二氧化硅壳层包覆NiO与Mo/HZSM-5物理混合对甲烷脱氢芳构化的促进作用

Jangeon Roha,1, Kihun Nama,1, Yong Hyun Lima, Yeseul Hwanga, Hae Won Ryua, Kyoungmin Kima, Gyeongmin Seoka, Yangho Jeonga, Jong Hun Kanga, Jungyeop Leeb, Jong-Ki Jeonb, Do Heui Kima,*()   

  1. a首尔国立大学化学工艺研究所, 化学与生物工程学院, 首尔 08826, 韩国
    b公州国立大学化学工程系, 天安 31080, 韩国
  • 收稿日期:2024-11-06 接受日期:2025-01-06 出版日期:2025-04-18 发布日期:2025-04-13
  • 通讯作者: * 电子信箱: dohkim@snu.ac.kr (D. H. Kim).
  • 作者简介:

    1共同第一作者.

  • 基金资助:
    韩国科学、信息通信技术与未来规划部(2021M3D3A1A01022109);碳中和工业战略技术发展计划(RS-2023-00261088)

Promotional effect of silica shell coated NiO physically mixed with Mo/HZSM-5 catalyst on methane dehydroaromatization

Jangeon Roha,1, Kihun Nama,1, Yong Hyun Lima, Yeseul Hwanga, Hae Won Ryua, Kyoungmin Kima, Gyeongmin Seoka, Yangho Jeonga, Jong Hun Kanga, Jungyeop Leeb, Jong-Ki Jeonb, Do Heui Kima,*()   

  1. aSchool of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, 1 Gwanak-ro, Gwanak-Gu, Seoul 08826, Republic of Korea
    bDepartment of Chemical Engineering, Kongju National University, Cheonan 31080, Republic of Korea
  • Received:2024-11-06 Accepted:2025-01-06 Online:2025-04-18 Published:2025-04-13
  • Contact: * E-mail: dohkim@snu.ac.kr (D. H. Kim).
  • About author:

    1Contributed equally to this work.

摘要:

甲烷脱氢芳构化(MDA)反应可将甲烷直接转化为苯、甲苯和二甲苯,在天然气转化领域具有显著应用潜力。前期研究表明Mo/HZSM-5与NiO通过物理混合提高了其催化MDA反应的活性和稳定性. 物理混合的NiO不仅促进了MoCx活性位点的分散, 而且由于Ni诱导碳纳米管(CNT)生长, 还减少了MoCx上积碳的形成. 然而, 当NiO粒径减小时, 其与MoOx间过强的相互作用会形成NiMoO4, 不利于MoCx的分散, 限制促进效果. 因此, 本文通过在NiO颗粒表面包覆不同尺寸(5、15和110 nm)的二氧化硅壳层以解决该问题. 实验表明, 当二氧化硅壳层粒径为15 nm时, 包覆的NiO催化剂上苯、甲苯和二甲苯收率和稳定性方面均显著提高; 当粒径为5 nm时, 其包裹的NiO催化剂上二甲苯收率最高, 约为7.2%. 结果表明, 随着二氧化硅壳层的引入, NiO粒径减小, 催化性能得到改善. 结合透射电镜-能量散射谱、X-射线衍射、CH4-程序升温表面反应、CO化学吸附、可见拉曼光谱和热重分析结果表明, 薄的二氧化硅壳层促进了MoCx的分散, 同时抑制了Ni-Mo复合氧化物的形成. 然而, 当NiO的尺寸减小到5 nm时, 反应过程中CNT在Ni上的生长受到抑制, 这对于减少Mo活性位点上的积碳形成至关重要, 因此使得Ni催化剂稳定性下降. 本研究以可控的方式引入二氧化硅壳层可以显著增强物理混合的NiO对MDA反应的促进作用.

关键词: 甲烷脱氢芳构化, Mo/HZSM-5, 苯-甲苯-二甲苯混合物, 物理混合, 氧化镍, 二氧化硅壳层, 碳纳米管

Abstract:

In our previous study, the activity and stability of the Mo/HZSM-5 catalyst were enhanced by mixing physically with NiO in methane dehydroaromatization (MDA) reaction. It has been confirmed that the physically mixed NiO not only promoted the dispersion of MoCx active sites but also reduced the coke formation on the MoCx owing to the CNTs growth on Ni. However, the promotional effect of NiO was limited when the particle size was reduced, due to the excessive interaction with MoOx (forming NiMoO4) which is detrimental to the MoCx dispersion. In this study, to overcome the limitation, silica shell on NiO particles with various sizes (5, 15, 110 nm) was introduced. The catalyst with silica shell coated NiO with the size of 15 nm exhibited a significant improvement in both BTX yield and stability, and the catalyst with silica shell coated NiO with the size of 5 nm achieved the highest maximum BTX yield, about 7.2%. This study demonstrates that the catalytic performance improved as the NiO particle size decreased with the introduction of the silica shell. Combined transmission electron microscopy-energy dispersive spectroscopy, X-ray diffraction, temperature-programmed surface reaction of methane, CO chemisorption, visible Raman, and thermogravimetric analysis allowed us to confirm that a thin silica shell further enhances the MoCx dispersion while preventing the formation of Ni-Mo complexes. However, when the size of NiO decreased to 5 nm, CNT growth on Ni was limited during the reaction, which is crucial for reducing coke formation on Mo active sites, thereby resulting in the decreased catalyst stabilization ability of Ni. Overall, this study indicates that the introduction of a silica shell in a controlled way can significantly enhance the promotional effect of physically mixed NiO on MDA.

Key words: Methane dehydroaromatization, Mo/HZSM-5, BTX, Physical mixing, NiO, Silica shell, Carbon nanotube