MCM-41分子筛上掺杂Al物种构型稳定性的理论研究  

Theoretical study on the stability of aluminum species doped MCM-41 silica

作　　者：王照猛 漆婷 张锦丰 谢红 司振兵[1] 杨华清[1] WANG Zhao-meng;QI Ting;ZHANG Jing-feng;XIE Hong;SI Zhen-bing;YANG Hua-qing(College of Chemical Engineering,Sichuan University,Chengdu,610065,China)

机构地区：[1]四川大学化学工程学院,四川成都610065

出　　处：《化学研究与应用》2018年第8期1372-1375,共4页Chemical Research and Application

基　　金：国家自然科学基金项目(21573154)资助

摘　　要：采用量子力学和分子力场相结合的方法,理论研究了在MCM-41分子筛骨架上掺杂Al物种构型的稳定性。其中,量子力学(QM)采用GGA-PBE交换相关泛函和DNP基组,分子力场(MM)采用Universal力场。研究结果表明,掺杂Al的MCM-41分子筛骨架上有三种铝物种构型,分别为–(Si O)3(Si OH)Al、–(Si O)2(Si OH)Al(OH)和–(Si O)(Si OH)Al(OH)2,简写为[Al-1],[Al-2]和[Al-3]。热力学分析结果表明,在100~600 K温度区间内,[Al-1]的结构是最稳定的。在100~300 K温度区间内,Al物种构型的稳定性顺序为[Al-1]>[Al-2]>[Al-3];在300~600 K温度区间内,Al物种构型的稳定性顺序为[Al-1]>[Al-3]>[Al-2]。同时表明,[Al-1]和[Al-3]的稳定性随着温度的升高而增加;[Al-2]的稳定性随着温度的升高而降低。在分子水平上明确掺杂Al的MCM-4分子筛骨架上的稳定构型对研究催化反应机理和设计新型高效催化剂具有重要的意义。The stability of aluminum doped MCM-41 silica has been theoretically investigated at the hybrid quantum mechanics(GGA-PBE,QM)and molecular mechanics(Universal,MM)level.There are three kinds of geometries for aluminum species doped MCM-41 silica,i.e.,–(SiO)3(SiOH)Al,–(SiO)2(SiOH)Al(OH)and–(SiO)(SiOH)Al(OH)2,marked as[Al-1],[Al-2]and[Al-3].Among them,over the 100~600 K range of temperatures,[Al-1]model is the most stable species.Over the 100~300 K range of temperatures,the stability of Al species decrease as[Al-1]>[Al-2]>[Al-3].Over the 300~600 K range of temperatures,the stability of Al species decrease as[Al-1]>[Al-3]>[Al-2].The increase of temperature is beneficial to the stability of[Al-1]and[Al-3],while the decrease of temperature is favorable to the stability of[Al-2].Theoretical study on the stability of aluminum species doped MCM-41 silica at the molecular level is of utmost importance to unravel the catalytic reaction mechanism and to design new high performing catalysts.

关 键 词：稳定性 热力学 AL-MCM-41 GGA-PBE 

分 类 号：O641.1[理学—物理化学]