合成气转化过程中金属表面的选择性和活性
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- 英文论文题名：The selectivity and activity of catalyst for syngas conversion
- 论文作者：王静波 ; 孙强 ; 苏海滨
- 英文论文作者：Jingbo Wang ; Qiang Sun ; Haibin Su ; School of Chemical Engineering ; Sichuan University ; College of Engineering ; Peking University ; School of Materials Science and Engineering ; Nanyang Technological University
- 年：2016
- 作者机构：四川大学化学工程学院;北京大学工学院;南洋理工大学材料科学与工程学院;
- 论文关键词：合成气 ; 费托过程 ; 选择性 ; 活性 ; 晶界
- 会议召开时间：2016-07-01
- 会议录名称：中国化学会第30届学术年会摘要集-第十八分会：电子结构理论方法的发展与应用
- 语种：中文
- 分类号：O643.36
- 学会代码：ZGHY
- 会议名称：中国化学会第30届学术年会-第十八分会 ; 电子结构理论方法的发展与应用
- 会议地点：中国辽宁大连
- 主办单位：中国化学会
- 学会名称：中国化学会
- 页数：1
- 文件大小：213k
- 原文格式：D
- 会议级别：全国
摘要
实验表明合成气转化过程中不同的金属有不同的选择性。Cu,Ni和Co分别催化得到甲醇,甲烷和长链烷烃;而为了得到长链醇,必须使用双金属催化剂。从微观层次上认识决定金属选择性和活性的因素,可以为催化剂的设计提供思路。首先针对典型的费托反应催化剂,在Cu(111),Co(111)和Ni(111)表面上,我们构建了包含24个基元反应的详细反应机理,通过能垒分析得到了优先的反应途径。Cu(111)作为吸附能力最弱的表面不能催化C-O键断裂反应,它只能连续加氢生成甲醇。反之具有最强吸附能力的Co可以催化C-O键断裂反应,生成CH_2和CH_3。在Co表面链增长反应的能垒低于生成CH_4的能垒,因此Co是生成长链烷烃的催化剂。与Co类似,Ni可以催化生成CH_2和CH_3。但与Co不同的是,链增长反应的高能垒阻碍了长链的形成。因此Ni是良好的生成CH_4的催化剂。进一步在Cu晶界结构上的研究表明晶界工程是改变催化剂活性和选择性的一种方法。Cu∑5(310)不仅加快了甲醇的生成,更重要的是可以生成长链醇。Cu∑5(310)更好的活性归因于低配位位点和局部结构的可塑性,因而降低了关键反应的能垒,改变了单金属Cu的选择性。
Typical Fischer-Tropsch catalysts display different selectivity and activity in catalyzing CO hydrogenation to diverse products.Understanding the underlying mechanism on why different metals exhibit different catalytic behaviors in FT process is essential to develop catalyst with novel property, such as enhancing ethanol production with low cost catalyst.In this section, firstly we present a comprehensive picture on the activity and selectivity of catalysts for FT process, and then we propose that Cu catalyst by grain boundary engineering is the better catalyst for higher alcohol synthesis.The results show that surface with strong binding capability promotes the dissociation reaction, meanwhile impedes the association reaction.Cu∑5(310) possess the capacity to catalyze the formation of CH_2 OH and CH_2, which cannot be produced on pure Cu(111), Cu(110), Cu(211) and even on Cu_(29) cluster.From CH_2, C_2 oxygenates is the major product.
Typical Fischer-Tropsch catalysts display different selectivity and activity in catalyzing CO hydrogenation to diverse products.Understanding the underlying mechanism on why different metals exhibit different catalytic behaviors in FT process is essential to develop catalyst with novel property, such as enhancing ethanol production with low cost catalyst.In this section, firstly we present a comprehensive picture on the activity and selectivity of catalysts for FT process, and then we propose that Cu catalyst by grain boundary engineering is the better catalyst for higher alcohol synthesis.The results show that surface with strong binding capability promotes the dissociation reaction, meanwhile impedes the association reaction.Cu∑5(310) possess the capacity to catalyze the formation of CH_2 OH and CH_2, which cannot be produced on pure Cu(111), Cu(110), Cu(211) and even on Cu_(29) cluster.From CH_2, C_2 oxygenates is the major product.
引文
[1]Jingbo,Wang.;Qiang,Sun.;Siewhwa,Chan.;Haibin,Su.Appl.Catal.A:General.2016,509:97.
[2]Jingbo,Wang.;Yoshiyuki,Kawazoe.;Qiang,Sun.;Siewhwa,Chan.;Haibin,Su.Surf.Sci.2016,645:30.
[3]Tat Thang,Doan.;Jingbo,Wang.;Kee Chun,Poon.;Desmond,C.L.Tan.;Bahareh,Khezri.;Haibin,Su.;Hirotaka,Sato.Angew.Chem.Int.Ed.DOI:10.1002/anie.201601727.
[2]Jingbo,Wang.;Yoshiyuki,Kawazoe.;Qiang,Sun.;Siewhwa,Chan.;Haibin,Su.Surf.Sci.2016,645:30.
[3]Tat Thang,Doan.;Jingbo,Wang.;Kee Chun,Poon.;Desmond,C.L.Tan.;Bahareh,Khezri.;Haibin,Su.;Hirotaka,Sato.Angew.Chem.Int.Ed.DOI:10.1002/anie.201601727.