Precise analysis of the framework Al (Al_F) at channel intersections of HZSM-5 zeolite is the basis of fine tuning of the spatial distribution of active sites within different pores which is critical to promote the catalytic performance in various applications. However, existing technologies cannot provide reliable quantitative results either in theory or practice due to the co-existence of Al pair and single Al. Here we report a new method based on toluene adsorption–desorption. As a promising probe, toluene can be preferentially adsorbed on Al_F at channel intersection under low loading (≤4 molecules/unit cell) due to spatial matching and energetic heterogeneity. After strengthening the toluene/Al_F affinity through replacing H⁺ by Na⁺ and designing a new stepwise TPD technique (toluene-STPD), the contents of Al_F atoms at channel intersections of HZSM-5 samples were successfully calculated by counting the desorbed toluene molecules based on the 1:1 stoichiometric relationship between adsorbed toluene and Al_F.

精确分析 HZSM-5 沸石通道交叉处的骨架 Al (Al _F ) 是微调不同孔内活性位点空间分布的基础，这对于提高各种应用中的催化性能至关重要。然而，由于Al对和单Al共存，现有技术在理论上或实践上都不能提供可靠的定量结果。在这里，我们报告了一种基于甲苯吸附-解吸的新方法。作为一种有前途的探针，由于空间匹配和能量异质性，甲苯可以在低负载（≤4分子/晶胞）下优先吸附在通道交叉处的Al _F上。通过 Na取代 H ⁺增强甲苯/Al _{F亲和力后}⁺并设计了一种新的逐步 TPD 技术（甲苯-STPD），根据吸附的甲苯和 Al 之间的 1:1 化学计量关系，通过对解吸的甲苯分子进行计数，成功计算了 HZSM-5 样品通道交叉处的 Al _{F原子含量F。} _