催化学报

催化学报 ›› 2021, Vol. 42 ›› Issue (8): 1404-1412.DOI: 10.1016/S1872-2067(20)63731-7

• 论文 • 上一篇    

酞菁铁中N4-Fe 2+的氧化还原化学和氧还原性能

阿努杰·库马尔a,b, 张英c, 贾茵a, 刘文a,#(), 孙晓明a,*()   

  1. a北京化工大学化学学院, 化工资源有效利用国家重点实验室, 北京市软物质高精尖中心, 北京 100029, 中国
    b印度GLA大学人文与应用科学研究所化学系, 北方邦马拉图, 印度
    c莫纳什大学化学院, 克莱顿, 澳大利亚
  • 收稿日期:2020-08-09 接受日期:2020-08-09 出版日期:2021-08-18 发布日期:2020-12-10
  • 通讯作者: 刘文,孙晓明
  • 作者简介:# wenliu@mail.buct.edu.cn
    *. 电话/传真: (010)64448751; 电子信箱: sunxm@mail.buct.edu.cn
  • 基金资助:
    国家自然科学基金(21675007);国家自然科学基金(21676015);国家自然科学基金(21520102002);国家自然科学基金(91622116);北京化工大学人才启动基金(buctrc201901);国家自然科学基金委员会(NSFC)与意大利外交与国际合作部(MAECI)合作项目(NSFC-MAECI 51861135202);国家重大科技专项(2018YFB1502401);国家重大科技专项(2018YFA0702002);牛顿高级学者基金(NAF\R1\191294);教育部长江学者和创新群体发展计划(IRT1205);教育部中央高校基本科研业务费专项资助, 中央高校发展长效机制经费项目

Redox chemistry of N4-Fe 2+ in iron phthalocyanines for oxygen reduction reaction

Anuj Kumara,b, Ying Zhangc, Yin Jiaa, Wen Liua,#(), Xiaoming Suna,*()   

  1. aState Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China
    bDepartment of Chemistry, Institute of Humanities and Applied Science, GLA University, Mathura 281406, India
    cSchool of Chemistry, Monash University, Wellington Road, Clayton 3800, VIC, Australia
  • Received:2020-08-09 Accepted:2020-08-09 Online:2021-08-18 Published:2020-12-10
  • Contact: Wen Liu,Xiaoming Sun
  • About author:#. E-mail: wenliu@mail.buct.edu.cn
    *. Tel/Fax: +86-10-64448751; E-mail: sunxm@mail.buct.edu.cn
  • Supported by:
    This work was supported by the National Natural Science Foundation of China(21675007);This work was supported by the National Natural Science Foundation of China(21676015);This work was supported by the National Natural Science Foundation of China(21520102002);This work was supported by the National Natural Science Foundation of China(91622116);Beijing University of Chemical Technology(buctrc201901);National Natural Science Foundation of China and Ministry of Foreign Affairs and International Cooperation, Italy(NSFC-MAECI 51861135202);the National Key Research and Development Project(2018YFB1502401);the National Key Research and Development Project(2018YFA0702002);the Royal Society and the Newton Fund through the Newton Advanced Fellowship award(NAF\R1\191294);the Program for Changjiang Scholars and Innovation Research Team in the University(IRT1205);the Fundamental Research Funds for the Central Universities, and the long-term subsidy mechanism from the Ministry of Finance and the Ministry of Education of PRC

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摘要：

准确理解金属大环配合物(如N4-Fe 2+)体系的氧化还原化学性能, 对氧还原反应(ORR)电催化剂的基础研究和合理设计具有重要意义. 本文采用微波法将三种不同酞菁铁类金属大环配合物吸附在碳纳米管上, 分别记为(NH2)4FePc@CNTs, (t-Bu)4FePc@CNTs和FePc@CNTs, 考察了取代基对Fe 3+/Fe 2+氧化还原电位的影响, 以及碱性介质中的氧还原反应催化活性. 结果表明, FePc@CNTs, (t-Bu)4FePc@CNTs和(NH2)4FePc@CNTs的ORR起始电位分别为0.98, 0.96和0.96 V, 而半波电位(E1/2)由高到低的顺序为FePc@CNTs (E1/2 = 0.91 V), (t-Bu)4FePc@CNTs (E1/2 = 0.87 V), (NH2)4FePc@CNTs (E1/2 = 0.83 V). 与20% Pt/C (E1/2 = 0.85 V)相比, FePc@CNTsFePc@CNTs具有优异的ORR性能. 在活性、稳定性和耐甲醇性方面, FePc@CNTs复合材料比其他复合材料表现出更高的ORR性能.
研究发现, FePc上的供电子基团可以显著改变N4-Fe 2+活性位点的电子云密度, 增加dz 2轨道(HOMO)的能量, 并观察到Fe 2+/Fe 3+氧化还原电位显著向阴极方向移动. 结果表明, 取代基的高电子贡献能力降低了HOMO和LUMO(O2的杂轨道*-轨道)之间的电子耦合, 从而降低了氧还原催化活性. 因此, FePc框架外围的供电子基团对ORR不利.
本文阐明了取代基电子效应-金属大环配合物氧化还原电位与ORR催化性能之间的关系, 为ORR催化剂活性中心的构建和调控提供了借鉴.

关键词: 酞菁铁, 取代效应, 氧还原反应, 碳纳米管, 活性描述符

Abstract:

A precise understanding of the redox chemistry of Nm-M n+ (like N4-Fe 2+) systems is essential for fundamental studies and rational design of Nm-M n+-based electrocatalysts for the oxygen reduction reaction (ORR). Herein, three different iron phthalocyanines (FePcs) adsorbed on carbon nanotubes ((NH2)4FePc@CNTs, (t-Bu)4FePc@CNTs, and FePc@CNTs) were evaluated to demonstrate the effect of the electron donating power of the substituents on the Fe 3+/Fe 2+redox potential of FePc@CNTs and the role of these composites as ORR mediators in alkaline media. The Fe 3+/Fe 2+redox potential of the FePcs was found to shift towards the cathodic region upon substitution with electron-donating groups. This up-field shift in the eg-orbital leads to a lower overlap between the onset potential of the Fe 3+/Fe 2+ redox couple and that of the ORR, and thus, the ORR activity decreased in the following order based on the substitution of FePc: ‒H > ‒t-Bu > ‒NH2.

Key words: Iron phthalocyanines, Substitution effect, Oxygen reduction reaction, Carbon nanotubes, Activity descriptor