Chinese Journal of Catalysis

Chinese Journal of Catalysis ›› 2025, Vol. 77: 110-122.DOI: 10.1016/S1872-2067(25)64762-0

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Origin of Brönsted acidity in germanosilicates from neighboring Ge-hydroxyl groups

Kun Lua, Qian Liua, Liyu Chena, Jilong Wangb, Zhenxuan Yuanf, Xiao Konga, Yunxing Baif, Jingang Jiangb, Yejun Guanb,d, Sicong Mac,*(), Hao Xub,d,*(), Weixin Huangf,*(), Zhipan Liuc,e, Peng Wub,d,*()   

  1. aSchool of Materials and Chemistry, University of Shanghai for Science and Technology, Shanghai 200093, China
    bState Key Laboratory of Petroleum Molecular & Process Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
    cState Key Laboratory of Metal Organic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
    dInstitute of Eco-Chongming, Shanghai 202162, China
    eShanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Key Laboratory of Computational Physical Science, Department of Chemistry, Fudan University, Shanghai 200433, China
    fKey Laboratory of Precision and Intelligent Chemistry, Hefei National Research Center for Physical Sciences at the Microscale, iChEM, Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, Anhui, China
  • Received:2025-04-13 Accepted:2025-06-04 Online:2025-10-18 Published:2025-10-05
  • Contact: *E-mail: pwu@chem.ecnu.edu.cn (P. Wu), hxu@chem.ecnu.edu.cn (H. Xu), huangwx@ustc.edu.cn (W. Huang), scma@mail.sioc.ac.cn (S. Ma).
  • Supported by:
    National Natural Science Foundation of China(22202132);National Natural Science Foundation of China(22222201);National Key R&D Program of China(2021YFA1501401);National Key R&D Program of China(2023YFB3810602)

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Abstract:

Constructing new Brönsted acid sites within zeolitic materials holds paramount importance for the advancement of solid-acid catalysis. Zeo-type germanosilicates, a class of metallosilicates with a neutral framework composed of tetravalent Ge and Si oxygen tetrahedrons, are conventionally considered not to generate Brönsted acid sites. Herein, we disclose an abnormal phenomenon with Ge-rich IWW-type germanosilicate (IWW-A) as an example that Ge-enriched germanosilicates are featured by mild Brönsted acidity. Using the art-of-state density functional theory calculation, 19F magic angle spinning nuclear magnetic resonance, microcalorimetric and ammonia infrared mass spectrometry- temperature-programmed desorption characterizations, the nature of germanosilicate's Brönsted acidity has been demonstrated to be closely related to the neighboring framework Ge-hydroxyl pairs. Besides, the contribution of Ge-OH groups to Brönsted acidity and the role of Ge-pair structure for maintaining mild acid strength have been elucidated. In catalytic cracking of n-hexane and methanol-to-olefins reaction, the IWW-A germanosilicate exhibit high light olefins selectivity, good recyclability and low carbon deposition, outperforming the benchmark zeolite catalyst, ZSM-5 aluminosilicate.

Key words: Germanosilicates, IWW, Brönsted acidity, Framework Ge-hydroxyl, Alkane cracking, Methanol-to-olefins