《Table 2Textural properties of HCh Cl‐Y, HCh OH‐Y and HNa Y samples before and after the hydrotherma

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《以胆碱为绿色无毒有机结构导向剂合成高硅Y型分子筛（英文）》

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a Estimated by the reflection intensities of the X‐ray diffraction peaks（1 1 1），（2 2 0） and（3 3 1）of the samples.

It is well known that the（hydro）thermal stability of zeolite at high temperature has a strong relationship with the frame‐work Si O2/Al2O3 ratio，which is a crucial factor for industrial applications.The exothermic peaks without weight variation above 800°C in the TG/DSC curves are attributed to the struc‐tural collapse of zeolite Y，which is used as a main evaluation of the thermal stability of zeolites at high temperature.Na‐Y starts to collapse at 970°C（Fig.S7），but the skeleton of ChCl‐Y and Ch OH‐Y remains stable until 1024 and 1030°C（Fig.2E and 2F）.The results are also additional evidence that our materials have unusually ultrahigh Si O2/Al2O3 ratio.The crystallinity change before and after steam treatment at high temperature is a measure of the hydrothermal stability of zeolites.The XRD pat‐terns of HChCl‐Y，HChOH‐Y and HNa‐Y（the correspond H‐form samples after ammonium ion exchange and calcination）before and after 100%steam treatment at 750°C for 2 h are shown inFig.5.This indicates that the crystallinity of HNa‐Y descents more steeply than that of HCh Cl‐Y and HCh OH‐Y after steam treatment.The crystallinity of HCh Cl‐Y and HCh OH‐Y retains54.2%and 56.6%，higher than 38.5%of HNa‐Y；BET specific surface area and t‐plot micropore surface area of HNa‐Y are obviously lower than that of HChCl‐Y and HChOH‐Y after steam treatment（Table 2）.The results indicate that Ch Cl‐Y and Ch OH‐Y exhibit a more superior hydrothermal and thermal stability owing to the higher framework SiO2/Al2O3 ratio.It is known that the bond energy of the silicon–oxygen bond（Si–O–Si）is higher than that of the aluminium–oxygen bond（Al–O–Si），so the Si–O–Si bond is more stable than the Al–O–Si bond.Ch Cl‐Y and Ch OH‐Y have higher Si–O–Si/Al–O–Si ratio than Na‐Y，which has been interpreted with the 29Si‐NMR spec‐trum（Fig.4）.Collectively，these studies confirm the practical advantages of increasing Y zeolite SiO2/Al2O3 ratio to improve the（hydro）thermal stability，which enhances the adaptation of Y zeolite for catalytic applications.