催化学报 ›› 2025, Vol. 74: 108-119.DOI: 10.1016/S1872-2067(25)64724-3

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Silicalite-1中CoOx物种在反应诱导下的重构机制以调控丙烷非氧化脱氢选择性

张启扬a,*(), Vita A. Kondratenkoa, 丁湘浓a, Jana Weissa, Stephan Bartlinga, Elizaveta Fedorovaa, 赵丹a,b,c, Dmitry E. Doronkinb, 王东旭d, Christoph Kubisa, Evgenii V. Kondratenkoa,*()   

  1. a莱布尼茨催化研究所, 罗斯托克, 德国
    b卡尔斯鲁厄理工学院化学技术与高分子化学研究所, 催化研究与技术研究所, 卡尔斯鲁厄, 德国
    c中国科学院大连化学物理研究所, 甲醇制烯烃国家工程实验室, 清洁能源国家实验室, 能源材料化学协同创新中心(iChEM), 辽宁大连 116023, 中国
    d马克斯·普朗克微结构物理研究所, 哈勒, 德国

Understanding the reaction-induced restructuring of CoOx species in silicalite-1 to control selectivity in non-oxidative dehydrogenation of propane

Qiyang Zhanga,*(), Vita A. Kondratenkoa, Xiangnong Dinga, Jana Weissa, Stephan Bartlinga, Elizaveta Fedorovaa, Dan Zhaoa,b,c, Dmitry E. Doronkinb, Dongxu Wangd, Christoph Kubisa, Evgenii V. Kondratenkoa,*()   

  1. aLeibniz-Institut für Katalyse e.V., D-18059 Rostock, Germany
    bInstitute for Chemical Technology and Polymer Chemistry, and Institute of Catalysis Research and Technology, Karlsruhe Institute of Technology, D-76131, Karlsruhe, Germany
    cNational Engineering Laboratory for Methanol to Olefins, Dalian National Laboratory for Clean Energy, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
    dMax Planck Institute of Microstructure Physics, 06120 Halle, Germany
  • Received:2025-01-28 Accepted:2025-03-08 Online:2025-07-18 Published:2025-07-20
  • Contact: *E-mail: Qiyang.Zhang@catalysis.de (Q. Zhang), Evgenii.kondratenko@catalysis.de (E. V. Kondratenko).

摘要:

丙烷非氧化脱氢(PDH)是大规模定向生产丙烯的重要途径. 尽管钴基催化剂有望替代当前使用的铂基或氧化铬基催化剂, 但由于对目标反应和副反应中活性位点种类的不确定性, 其进一步发展受到限制. 因此, 本文系统研究了基于Silicalite-1分子筛负载的具有不同氧化还原特性的CoOx物种中氧化态CoOx和金属态Co0物种在PDH反应中的作用. 通过亚毫秒级和秒级时间分辨的丙烷脉冲实验(脉冲量分别约13和2200 nmol), 并结合深度的催化剂表征及不同丙烷转化率下的PDH测试, 揭示了反应诱导的CoOx还原对产物选择性的影响机制. 研究结果表明, 丙烷可快速与CoOx反应生成丙烯、碳氧化物和水; 生成的Co0物种在结焦和裂解反应中表现出高活性; 但当此类物种尺寸小于2 nm时, 由于碳物种对活性位点的覆盖显著抑制了这些副反应的发生; 未被覆盖的表面钴位点可选择性催化丙烷脱氢生成丙烯. 性能最优的催化剂展现出高于商用K-CrOx/Al2O3催化剂的活性, 并在工业条件下的10次脱氢/再生循环中保持稳定运行. 在550 °C、平衡丙烷转化率52%和丙烯选择性95%的条件下, 生成丙烯的时空产率达到0.97 kg·h-1·kg-cat-1.

关键词: 丙烷, 脱氢, 丙烯, 钴, 反应机理

Abstract:

Non-oxidative dehydrogenation of propane (PDH) is an important route for large-scale on purpose propene production. Although cobalt-based catalysts are promising alternatives to currently used platinum- or chromium oxide-based catalysts, their further developments are hindered by the uncertainties related to the kind of the active sites involved in the desired and side reactions. To contribute to closing such a gap, we systematically investigate the role of oxidized CoOx and metallic Co0 species in the PDH reaction over catalysts based in Silicalite-1 with supported CoOx species differing in their redox properties. C3H8 pulse experiments with sub-millisecond and second resolution at pulse sizes of about 13 and 2200 nmol, respectively, combined with in-depth catalyst characterization and PDH tests at different propane conversions enabled us to understand how the reaction-induced reduction of CoOx affects product selectivity. Propane readily reacts with CoOx to yield propene, carbon oxides and water. The formed Co0 species show high activity to coking and cracking reactions. However, if the size of such species is below 2 nm, these undesired reactions are significantly hindered due to the coverage of the active sites by carbon-containing species. The remaining uncovered surface Co0 sites selectively dehydrogenate propane to propene. The best-performing catalyst showed higher activity than a commercial-like K-CrOx/Al2O3 and operated durable in a series of 10 dehydrogenation/regeneration cycles under industrial relevant conditions. The space time yield of propene formation of 0.97 kg·h-1·kgcat-1 was achieved at 550 °C, 52% equilibrium propane conversion and 95% propene selectivity.

Key words: Propane, Dehydrogenation, Propene, Cobalt, Mechanism