物理化学学报 >> 2013, Vol. 29 >> Issue (10): 2245-2254.doi: 10.3866/PKU.WHXB201308201

催化和表面科学 上一篇    下一篇

SiO2气凝胶负载的Ni催化剂在甲烷部分氧化制合成气反应中的催化性能及稳定性

李琪, 侯玉慧, 董玲玉, 黄铭湘, 翁维正, 夏文生, 万惠霖   

  1. 厦门大学化学化工学院, 固体表面物理化学国家重点实验室, 醇醚酯化工清洁生产国家工程实验室, 福建省理论计算化学重点实验室, 福建厦门 361005
  • 收稿日期:2013-06-07 修回日期:2013-08-20 发布日期:2013-09-26
  • 通讯作者: 夏文生, 万惠霖 E-mail:wsxia@xmu.edu.cn;hlwan@xmu.edu.cn
  • 基金资助:

    国家重点基础研究发展计划(973) (2010CB732303);国家自然科学基金(21033006, 21373169)及长江学者和创新团队发展计划(IRT1036)资助

Catalytic Behaviors and Stability of Aerogel Silica-Supported Ni Catalysts for the Partial Oxidation of Methane into Synthesis Gas

LI Qi, HOU Yu-Hui, DONG Ling-Yu, HUANG Ming-Xiang, WENG Wei-Zheng, XIA Wen-Sheng, WAN Hui-Lin   

  1. State Key Laboratory of Physical Chemistry of Solid State Surfaces, National Engineering Laboratory for Green Chemical Productions of Alcohols-Ethers-Esters, Fujian Province Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian Province, P. R. China
  • Received:2013-06-07 Revised:2013-08-20 Published:2013-09-26
  • Contact: XIA Wen-Sheng, WAN Hui-Lin E-mail:wsxia@xmu.edu.cn;hlwan@xmu.edu.cn
  • Supported by:

    The project was supported by the National Key Basic Research Program of China (973) (2010CB732303), National Natural Science Foundation of China (21033006, 21373169), and Programfor Changjiang Scholars and Innovative Research Teamin Universities, China (IRT1036).

摘要:

以常压有机溶剂置换(A)和溶剂置换-表面改性(B)方式制备的两种SiO2气凝胶(SiO2-A(或B)型气凝胶,记为SiO2-A(or B)G)为载体, 采用常规浸渍法和聚乙烯吡咯烷酮(PVP)添加浸渍法合成不同SiO2气凝胶负载的Ni/SiO2催化剂, 并考察其催化的甲烷部分氧化(POM)制合成气的反应性能. 结果表明, 各催化剂的初始反应性能相近, 但Ni/SiO2-BG的POM稳定性明显较Ni/SiO2-AG的差, 而PVP添加制备的催化剂稳定性则获明显改善, Ni/SiO2-AG-PVP、Ni/SiO2-BG-PVP上POM稳定性相近. 结合X射线衍射(XRD)、程序升温还原反应(H2-TPR)、高分辨透射电镜(TEM)和Brunauer-Emmett-Teller (BET)等表征结果的分析发现: (1) SiO2-AG表面上存在一定量的羟基, 可促进亲水性金属物种与其的相互作用, 而SiO2-BG表面上基本为有机基团, 与亲水性金属物种几乎无作用; (2) PVP的存在可使金属物种进入亲/疏水载体孔道深处, 抑制焙烧中载体骨架的收缩和金属颗粒的生长, 进而促进金属-载体的相互作用. 这二者均能有效地提高催化剂的POM反应稳定性.

关键词: SiO2, 气凝胶, 甲烷部分氧化, 羟基, PVP, 稳定性

Abstract:

Two types of aerogel silica, denoted as SiO2-A(or B)G are synthesized with either solvent substitution (A) or solvent substitution-surface modification (B) under atmospheric conditions. Aerogel silicasupported Ni catalysts are then prepared via impregnated (IM) and polyvinylpyrrolidone (PVP)-added IM methods, and their performances for the partial oxidation of methane (POM) are investigated. The similar initial catalytic performances (activity and selectivity) are observed over the different Ni/SiO2 catalysts. With respect to POMstability, Ni/SiO2-BG is significantly worse than Ni/SiO2-AG, while catalysts with PVP addition (during preparation) exhibit a significant improvement. In this case, Ni/SiO2-BG-PVPis comparable to Ni/SiO2-AG-PVP. We characterize the catalysts with X-ray diffraction (XRD), temperature-programmed hydrogen reduction (H2-TPR), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) analysis. We find that there are hydroxyls on the SiO2-AG surface that favor their interaction with hydrophilic metal species, while on the SiO2-BGsurface there are organic groups that do not interact with hydrophilic metal species. In addition, with the help of PVP, metal species can access the deep pores of hydrophilic/hydrophobic silica gels. Then, the contraction of the silica framework and the growth of metal particles are inhibited during calcinations, enhancing interactions between Ni and the silica gels. These (benefits fromsurface hydroxyls and PVP) result in significant improvements in the catalysts with respect to POMstability.

Key words: SiO2, Aerogel, POM, Hydroxyl, PVP, Stability

MSC2000: 

  • O643