物理化学学报
物理化學學報
물이화학학보
ACTA PHYSICO-CHIMICA SINICA
2013年
5期
1035-1040
,共6页
氧化镁%分子筛%水热稳定性%多级孔结构
氧化鎂%分子篩%水熱穩定性%多級孔結構
양화미%분자사%수열은정성%다급공결구
MgO%Zeolite%Hydrothermal stability%Hierarchical porosity
通过焙烧将分散在多孔氧化硅母体中的硝酸镁转化成高分散的MgO物种,然后使用四丙基氢氧化铵(TPAOH)作为结构导向剂,将含MgO的母体通过水热晶化合成MgO/silicalite-1分子筛复合物. X射线衍射(XRD)、能量X射线光谱(EDX)和透射电镜(TEM)的结果表明MgO物种被均匀地分散在silicalite-1分子筛晶体中.将酸处理脱除氧化镁前后的样品在100%水蒸汽800°C条件下老化,结果表明MgO的引入有效地提高了分子筛的水热稳定性.此外,酸洗脱除MgO/silicalite-1分子筛中的MgO提高了分子筛结晶度,同时引入了一定的介孔. N2物理吸附-脱附数据证明了酸洗后分子筛中介孔的存在.水热稳定性的提高和介孔的引入对于在高温下保持催化剂的孔道结构,提高催化剂的抗积碳能力,降低催化剂的失活速率以及延长催化剂的使用寿命起着非常重要的作用.
通過焙燒將分散在多孔氧化硅母體中的硝痠鎂轉化成高分散的MgO物種,然後使用四丙基氫氧化銨(TPAOH)作為結構導嚮劑,將含MgO的母體通過水熱晶化閤成MgO/silicalite-1分子篩複閤物. X射線衍射(XRD)、能量X射線光譜(EDX)和透射電鏡(TEM)的結果錶明MgO物種被均勻地分散在silicalite-1分子篩晶體中.將痠處理脫除氧化鎂前後的樣品在100%水蒸汽800°C條件下老化,結果錶明MgO的引入有效地提高瞭分子篩的水熱穩定性.此外,痠洗脫除MgO/silicalite-1分子篩中的MgO提高瞭分子篩結晶度,同時引入瞭一定的介孔. N2物理吸附-脫附數據證明瞭痠洗後分子篩中介孔的存在.水熱穩定性的提高和介孔的引入對于在高溫下保持催化劑的孔道結構,提高催化劑的抗積碳能力,降低催化劑的失活速率以及延長催化劑的使用壽命起著非常重要的作用.
통과배소장분산재다공양화규모체중적초산미전화성고분산적MgO물충,연후사용사병기경양화안(TPAOH)작위결구도향제,장함MgO적모체통과수열정화합성MgO/silicalite-1분자사복합물. X사선연사(XRD)、능량X사선광보(EDX)화투사전경(TEM)적결과표명MgO물충피균균지분산재silicalite-1분자사정체중.장산처리탈제양화미전후적양품재100%수증기800°C조건하노화,결과표명MgO적인입유효지제고료분자사적수열은정성.차외,산세탈제MgO/silicalite-1분자사중적MgO제고료분자사결정도,동시인입료일정적개공. N2물리흡부-탈부수거증명료산세후분자사중개공적존재.수열은정성적제고화개공적인입대우재고온하보지최화제적공도결구,제고최화제적항적탄능력,강저최화제적실활속솔이급연장최화제적사용수명기착비상중요적작용.
Hierarchical MgO/silicalite-1 composites were synthesized via hydrothermal treatment of MgO-supported porous silica using tetrapropylammonium hydroxide (TPAOH) as a template. MgO species were introduced into porous silica via solid-state grinding and subsequent calcination. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) results indicated that MgO was uniformly distributed in the zeolite crystals. The hydrothermal stability of MgO/silicalite-1 before and after acid washing was detected by treatment at 800 °C in 100%steam for 10 h. The introduction of MgO increased the hydrothermal stability of MgO/silicalite-1 samples. Furthermore, acid washing could remove MgO impurities, increasing the relative crystal inity of samples compared with that of calcined MgO/silicalite-1 and introducing mesopore into zeolite simultaneously. N2 adsorption-desorption measurements indicated that mesopores were generated in the zeolite crystals by the removal of MgO species. The improved hydrothermal stability and the generation of mesopores in these MgO/silicalite-1 samples play important roles in preserving zeolite structure, enhancing coke tolerance, slowing deactivation, and extending catalyst life during high-temperature reaction.
