六方氮化硼氧化模式的密度泛函理论研究  

Density Functional Theory Study of Hexagonal Boron Nitride Oxidation Mode

作　　者：马莹[1] 陈维希 刘羽辰 刘子义 吴涛[1] 陆安慧[1] 王东琪 Ma Ying;Chen Weixi;Liu Yuchen;Liu Ziyi;Wu Tao;Lu An-Hui;Wang Dongqi(State Key Laboratory of Fine Chemicals,Liaoning Key Laboratory for Catalytic Conversion of Carbon Resources,School of Chemistry,School of Chemical Engineering,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]大连理工大学精细化工国家重点实验室、辽宁省碳资源催化转化重点实验室、化学学院、化工学院,大连116024

出　　处：《化学学报》2025年第1期52-59,共8页Acta Chimica Sinica

基　　金：国家自然科学基金(Nos.21733002,22209018)资助.

摘　　要：六方氮化硼(h-BN)因其在催化轻质烷烃氧化脱氢(ODH)反应中表现出高反应活性、高烯烃选择性而受到越来越多的关注.之前对反应机理的研究表明,含氧硼物种(如>BOH、>BOOB<)与催化剂活性密切相关,但对h-BN可能的氧化模式和氧化模型的合理构建缺少系统研究和分析.本项工作建立了多种可能的含氧硼物种的模型,这些模型的区别在于氧化物种的类型(单氧与过氧)、氧化的位置(zigzag边或armchair边上的B或N位点)以及含氧基团的数量(氧化程度)等方面.研究从热力学角度评估了它们的稳定性,并计算了含氧硼物种的^(11)B固体核磁位移和谐振频率,提出了h-BN的zigzag边缘官能团化是其主要的氧化物种.为了解决量子化学谐振频率被高估的问题,研究进而采用硼基小分子拟合了含硼化合物的谐振频率校正因子,数值为0.9658(B3LYP/6-311G(d,p)).这项工作明确了氮化硼及其含氧物种的模型简化思路,为应用简化模型计算其热力学和核磁、振动光谱等性质提供了可行方案,有助于采用理论手段研究硼基催化反应的机理和各驻点的性质,为硼基催化体系的优化和理性设计提供理论依据.Propylene is one of the important raw chemical materials for producing polypropylene,epichlorohydrin and other chemical products.Propylene is traditionally produced by petroleum steam cracking,which is energy demanding and suffers from coking.In contrast,boron-based oxidative dehydrogenation(ODH)of light alkanes offers an alternative strategy with low energy cost and free of coking,and is growing as a promising protocol in the value-added conversion of shale gas and natural gas.Owing to the lack of molecular level of knowledge of the reaction system,there are many issues related to the underlying mechanism remain in debate,and the extensive mechanistic study relies on the choice of catalyst model to be used in computational studies and in interpreting experimental phenomena.In this work,concerning the importance of oxygenated boron species in the ODH of light alkanes,the oxidation modes of hexagonal boron nitride(h-BN)were evaluated by means of density functional theory(DFT)method to provide insights on the speciation of oxidized h-BN under ODH conditions,which is vital to understand ODH reaction catalyzed by boron-containing materials and to determine sensible choices of ox-ygenated models.Based on previous investigations,in which oxygenated boron species,e.g.>BOH,>BOB<,>BOOB<,were reported to play crucial role in forming active sites,various oxidation models of h-BN were prepared,differing from each other in the type of oxo species(mono-oxo vs peroxo),the position to be oxidized(B or N sites at zigzag or armchair edge),and the quantity of oxygenated groups(the extent of oxidization).The stability of these models were studied from the ther-modynamic perspective,and the ^(11)B nuclear magnetic resonance(^(11)B NMR)and harmonic vibrational modes of oxygenated boron species were calculated.The results show that zigzag-edges of h-BN is the main region to accommodate oxygenated boron species under ODH conditions.In order to reproduce the vibrational frequencies of oxygenated boron species measured in experimental stu

关 键 词：六方氮化硼的氧化模式 密度泛函理论 丙烷的氧化脱氢 热力学稳定性 红外分析 ^(11)B核磁共振 

分 类 号：TQ128[化学工程—无机化工] TQ426