硅锗超大孔分子筛的合成与改性及其催化应用研究进展
Research progress on synthesis,modification,and catalytic application of extra-large porous germanosilicate zeolites
详细介绍了硅锗分子筛作为一种关键多孔材料的核心特性与应用价值,重点聚焦于锗元素在分子筛骨架中的独特作用。深入分析锗的易水解特性如何被转化为优势,例如UTL型硅锗分子筛可利用选择性脱锗机制,通过ADOR(组装-分解-重整-再组装)或逆Sigma转化方法,在温和或极端条件下(如不同pH和温度)脱除富锗d4r单元形成层状前驱体,进而重构为新型高硅拓扑结构如IPC-n系列或OKO型分子筛,这一过程充分展示了锗位点的有序性如何实现缺陷可控和结构精准调控。同时,还细致分析了硅锗分子筛在催化应用中的表现,包括通过脱锗补硅提升水热稳定性、引入Ti或Sn等活性位点以增强酸催化性能,并在反应如糠醛的Meerwein-Ponndorf-Verley转化或蔗糖制羟甲基糠醛中显示出优异的选择性和效率,突显了非典型锗活性位点的潜力。尽管锗分子筛面临水热稳定性差、锗源成本高及ADOR方法适用范围有限(仅适用于UTL、UOV等特定骨架)的挑战,但通过拓扑转变技术已成功衍生多种新结构,为分子筛设计开辟了新路径,未来需深入探究锗的成核机制和晶化行为,以开发更普适的重构策略并拓展其在多功能催化剂中的应用前景。
The core properties and application value of germanosilicate zeolites as a key porous material are introduced,with a focus on the unique role of germanium in the zeolite framework.It delves into how the easy hydrolysis characteristics of germanium can be transformed into an advantage.For example,through utilizing selective germanium removal mechanism via ADOR (assembly-disassembly-organization-reassembly) or reverse Sigma transformation methods,UTL-type germanosilicate zeolites can get rid of d4r units under mild or extreme conditions (such as different pH values and temperatures) to form layered precursors that are further reconstructed into novel high-silicon topological structures such as IPC-n series or OKO-type zeolites.This process demonstrates fully how the ordered germanium sites enable to achieve controlled defects and precise structural regulation.The account also analyzes meticulously the performance of germanosilicate zeolites in catalytic applications,such as enhancing hydrothermal stability by silicon replacement via germanium removal,adding active sites such as Ti or Sn to improve acid catalysis performance,and showcasing excellent selectivity and efficiency in reactions like the Meerwein-Ponndorf-Verley transformation of furfural or the conversion of sucrose to hydroxymethylfurfural.These reactions highlight the potential of non-typical germanium active sites.Despite challenges such as poor hydrothermal stability,high germanium source cost,and limited applicability of ADOR method (only suitable for specific frameworks like UTL and UOV),various new structures have been successfully derived through topological transformation techniques.This has opened new pathways for zeolite design.Further investigation into the nucleation mechanism and crystallization behavior of germanium is required to develop more universal reconstruction strategies and expand its application potential in multifunctional catalysts.
硅锗分子筛 / 催化应用 / 改性技术 / 合成技术 / 超大孔
germanosilicate molecular sieves / catalytic application / modification technology / synthetic technology / extra-large pores
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国家能源集团化工公司科技创新项目(MZYHG-2022-44)
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