CAJ | 학술논문

采用液相离子交换(LPIE)法制备了不同离子交换度的CeY分子筛。运用电感耦合等离子发射光谱(ICP-AES)、X射线衍射(XRD)、N2吸附等温线和氨气程序升温脱附(NH3-TPD)等方法对其进行表征，采用原位傅里叶变换红外(in situ FTIR)光谱技术分别以吡啶和噻吩作为探针分子研究了Ce改性对Y型分子筛酸性能和催化转化性能的影响规律。结果表明， Ce离子改性不改变Y型分子筛晶体的基本骨架，但改变其精细结构。分子筛改性过程中Ce物种优先定位于方钠石(SOD)笼，随着稀土离子含量增大，逐渐出现在超笼中。 Ce离子交换过程中产生一定量的Br?nsted (B)酸中心，且其量与强度随着Ce含量的增大均呈现先增加后平稳的趋势。同时， Ce离子交换产生与非骨架铝物种和铈物种有关的两种强度不同的Lewis (L)酸中心，且两者均随着Ce含量的增大而增大。噻吩吸附红外光谱表明，由于Ce离子改性产生的强B酸中心可导致噻吩在室温条件下即可发生质子化反应，质子化的噻吩分子可进一步发生低聚反应。而稀土物种与B酸中心的协同作用有利于低聚反应的发生。
채용액상리자교환(LPIE)법제비료불동리자교환도적CeY분자사。운용전감우합등리자발사광보(ICP-AES)、X사선연사(XRD)、N2흡부등온선화안기정서승온탈부(NH3-TPD)등방법대기진행표정，채용원위부리협변환홍외(in situ FTIR)광보기술분별이필정화새분작위탐침분자연구료Ce개성대Y형분자사산성능화최화전화성능적영향규률。결과표명， Ce리자개성불개변Y형분자사정체적기본골가，단개변기정세결구。분자사개성과정중Ce물충우선정위우방납석(SOD)롱，수착희토리자함량증대，축점출현재초롱중。 Ce리자교환과정중산생일정량적Br?nsted (B)산중심，차기량여강도수착Ce함량적증대균정현선증가후평은적추세。동시， Ce리자교환산생여비골가려물충화시물충유관적량충강도불동적Lewis (L)산중심，차량자균수착Ce함량적증대이증대。새분흡부홍외광보표명，유우Ce리자개성산생적강B산중심가도치새분재실온조건하즉가발생질자화반응，질자화적새분분자가진일보발생저취반응。이희토물충여B산중심적협동작용유리우저취반응적발생。
Y-type zeolites with different cerium ion content were prepared by liquid phase ion exchange (LPIE) and their structural properties were characterized by inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray diffraction (XRD), N2 adsorption isotherm, and temperature-programmed desorption of ammonia (NH3-TPD). The influence of cerium ion modification of the Y-type zeolites on the acidity and catalytic behavior was studied by in situ Fourier transform infrared spectroscopy (in situ FTIR) techniques with pyridine and thiophene as probe molecules. The results indicate that the original crystal structures of the zeolites remain unchanged after modification with cerium ions. During the modification process the Ce species tend to be located in sodalite (SOD) cages after calcination and remain in the supercages upon a gradual increase in Ce cation content. The amount and strength of the Br?nsted (B) acid sites in the zeolites generated by the modification increases initial y and then stabilizes with an increase in Ce ion content. The strong and weak Lewis (L) acid sites related to the non-framework aluminum and the rare earth species increase continuously during the modification process. Thiophene adsorption FTIR spectra indicate that the adsorbed thiophene molecules protonate at the strong Br?nsted acid sites of the zeolites. The protonated products then oligomerize. The synergy between Ce species and B acid sites is favorable for the thiophene oligomerization reaction.