表面沉积非金属调控金属氧化物在氧化反应中的催化选择性
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- 英文论文题名：Tuning Catalytic Selectivity of Oxidative Catalysis through Deposition of Nonmetallic Atoms in Surface Lattice of Metal Oxides
- 论文作者：刘娟娟 ; 张适然 ; 范杰 ; Franklin Tao
- 英文论文作者：Juanjuan Liu ; Shiran Zhang ; Jie Fan ; Franklin Tao ; Zhejiang University ; University of Kansas
- 年：2016
- 作者机构：浙江大学化学系;University of Kansas;
- 论文关键词：催化选择性 ; 乙烷 ; 乙烯 ; 氧化脱氢 ; 表面晶格氧
- 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-第十五分会：表界面结构调控与催化
- 语种：中文
- 分类号：O643.3
- 学会代码：ZGHY
- 会议名称：中国化学会第30届学术年会-第十五分会 ; 表界面结构调控与催化
- 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：248k
- 原文格式：D
- 会议级别：全国
摘要
氧化反应中产物选择性的调控是多相催化中重要的研究课题1。金属催化剂可以通过合金化来改变分子氧的解离能垒进而调控其催化选择性2。而对于金属氧化物来说,则需要采用不同的方法。本文我们通过在金属氧化物表面上沉积非金属有效地抑制了反应分子的完全氧化,提高了催化反应的选择性。在乙烷氧化脱氢制乙烯反应中,Six-Co_3O_4表现出比纯Co_3O_4高得多的乙烯选择性。通过O182同位素交换等实验,我们证实了Six-Co_3O_4的高选择性主要来源于Si对Co_3O_4表面晶格氧原子活性的抑制。另外,DFT理论计算也表明O_2在Six-Co_3O_4上解离的能垒以及表面氧空位的跃迁能垒均高于纯Co_3O_4,进一步证实Si的存在影响了Co_3O_4的完全氧化能力,促使反应由完全氧化转为选择性氧化。我们将这种在金属氧化物表面沉积非金属调控催化选择性的方法成功拓展到了Gex-Co_3O_4体系。
Catalytic selectivity for producing an ideal product is a topic for chemical transformations through heterogeneous catalysis.Tuning catalytic selectivity by integrating second metal to form an alloy has been well demonstrated in literatures.Here we report a new method to tune catalytic selectivity in oxidative catalysis through deposition nonmetallic atoms in surface lattice of metal oxides,which can enhance selectivity through suppression of complete oxidation of reactant molecules.Six-Co_3O_4 exhibits much higher selectivity for ethylene production through oxidative dehydrogenation of ethane compared to pure Co_3O_4.The suppression of activity of surface lattice oxygen atoms was evidenced by isotopic O182 exchange experiments results.Also,DFT calculations show activation barriers for O_2 dissociation and energy barriers for hopping surface oxygen vacancies of Six-Co_3O_4 are obviously higher than those of pure Co_3O_4,respectively.This new approach for increasing catalytic selectivity is further confirmed by observed higher ethylene selectivity on Ge0.2-Co_3O_4 than pure Co_3O_4.
Catalytic selectivity for producing an ideal product is a topic for chemical transformations through heterogeneous catalysis.Tuning catalytic selectivity by integrating second metal to form an alloy has been well demonstrated in literatures.Here we report a new method to tune catalytic selectivity in oxidative catalysis through deposition nonmetallic atoms in surface lattice of metal oxides,which can enhance selectivity through suppression of complete oxidation of reactant molecules.Six-Co_3O_4 exhibits much higher selectivity for ethylene production through oxidative dehydrogenation of ethane compared to pure Co_3O_4.The suppression of activity of surface lattice oxygen atoms was evidenced by isotopic O182 exchange experiments results.Also,DFT calculations show activation barriers for O_2 dissociation and energy barriers for hopping surface oxygen vacancies of Six-Co_3O_4 are obviously higher than those of pure Co_3O_4,respectively.This new approach for increasing catalytic selectivity is further confirmed by observed higher ethylene selectivity on Ge0.2-Co_3O_4 than pure Co_3O_4.
引文
[1]Matsubu,J.;Yang,V.;Christopher,P.;J.Am.Chem.Soc.2015,6,7798.
[2]Jin,X.;Dang,L.;Lohrman,J.;Subramaniam,B.;Chaudhari,R.ACS Nano 2013,7,1309.
[2]Jin,X.;Dang,L.;Lohrman,J.;Subramaniam,B.;Chaudhari,R.ACS Nano 2013,7,1309.