催化学报 ›› 2020, Vol. 41 ›› Issue (12): 1855-1863.DOI: 10.1016/S1872-2067(20)63638-5

• 论文 • 上一篇    下一篇

基于尖晶石型混合金属钴矿的高效析氧电催化性能

陶磊明a,b, 郭鹏虎a, 朱伟玲a, 李天乐a, 周贤太d, 傅永庆c, 余长林a, 纪红兵a,d   

  1. a 广东石油化工学院理学院, 广东茂名 525000, 中国;
    b 华中科技大学武汉光电国家研究中心, 湖北武汉 430074, 中国;
    c 诺森比亚大学工程与环境学院, 纽卡斯尔, 英国;
    d 中山大学化学学院, 精细化工研究院, 广东广州 510275, 中国
  • 收稿日期:2020-03-11 修回日期:2020-04-14 出版日期:2020-12-18 发布日期:2020-08-14
  • 通讯作者: 纪红兵, 余长林
  • 基金资助:
    国家自然科学基金(21938001,21576302,21878344和201961160741);国家自然科学基金委-中国石化股份公司石油化工联合基金(U1663220);广东省重点研发计划(2019B110206002);广东省教育厅特色创新项目(2018KTSCX144,2016KTSCX087);广东珠江人才计划地方创新研究团队项目(2017BT01C102);广东省高校珠江学者计划(2019);广东普通高校重点项目<自然>(2019KZDXM010);广东省基础与应用基础研究基金(2019A1515011249);广东石油化工学院自然科学基金科研基金(2019rc019,2019rc053);英国工程与物理科学研究委员会(EPSRC)提供资助(EP/P018998/1);英国皇家学会和中国国家自然科学基金委员会的牛顿交流基金(IE161019).

Highly efficient mixed-metal spinel cobaltite electrocatalysts for the oxygen evolution reaction

Leiming Taoa,b, Penghu Guoa, Weiling Zhua, Tianle Lia, Xiantai Zhoud, Yongqing Fuc, Changlin Yua, Hongbing Jia,d   

  1. a School of Science, Guangdong University of Petrochemical Technology, Maoming 525000, Guangdong, China;
    b Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China;
    c Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK;
    d Fine Chemical Industry Research Institute, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, Guangdong, China
  • Received:2020-03-11 Revised:2020-04-14 Online:2020-12-18 Published:2020-08-14
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (21938001, 21576302, 21878344, 21961160741), Natural Science Foundation of China-SINOPEC Joint Fund (U1663220), Featured Innovation Project of Guangdong Education Department (2018KTSCX144, 2016KTSCX087), Guangdong Provincial Key R&D Programme (2019B110206002), the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program (2017BT01C102), Scientific Research Fund of Natural Science Foundation of Guangdong University of Petrochemical Technology (2019rc019, 2019rc053), Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme (2019), Key Natural Science Research Projects of Guangdong Provincial Universities (2019KZDXM010), Guangdong Basic and Applied Basic Research Foundation (2019A1515011249), the UK Engineering and Physical Sciences Research Council (EPSRC) for support under grant EP/P018998/1, and Newton Mobility Grant (IE161019) through the Royal Society and the National Natural Science Foundation of China.

摘要: 尖晶石钴矿(例如ACo2O4,其中A=Mn,Fe,Co,Ni,Cu或Zn的阳离子取代)是一种精确调控其电子结构/性质,并因此改善相应的电催化水分解析氧(OER)性能的有前途的策略.然而,有关它的基本原理和机制尚未完全理解.为了确定尖晶石氧化物在OER中的作用,已有实验和理论报道.例如,Prabu发现Ni3+离子取代NiCo2O4的八面体位点可以显着提高OER性能;Hutchings报道OER性能提高源自Co3O4八面体Co3+的活性位;Wei研究发现MnCo2O4八面体位置的Mn3+离子是OER的活性位点.尽管多数研究没有对此给出清晰的解释,但这些研究清楚地表明,尖晶石氧化物对OER的电催化性能在很大程度上取决于过渡金属阳离子(A)的化合价态及其在尖晶石结构中的相应位点分布.本文旨在合成具有同种形貌的尖晶石ACo2O4混合金属有机骨架(MMOFs)材料,通过A位引入外层d电子数从5到10的过渡金属元素,如Mn,Fe,Co,Ni,Cu和Zn,系统研究催化水分解析氧机理.基于实验详细分析了不同阳离子的取代和其OER的催化行为,在获得的六种尖晶石ACo2O4催化剂中,FeCo2O4催化剂在碱性溶液中具有出色的OER性能和稳定性,其在电流密度10mA·cm-2的超电势下164mV.催化剂的电荷传输性能与离子和空位扩散的跳跃率密切相关.我们使用密度泛函理论计算阳离子在ACo2O4晶体中的扩散以及扩散的活化能,并且计算过程考虑自旋的激发能.使用VASP的搜索过渡态方法(NEB-DMTS)确定离子扩散的最小能量反应路径.结果表明,尖晶石钴矿ACo2O4晶格中的Fe取代可以显著加速电荷转移,从而获得增强的电化学性能.由第一性原理计算Fe阳离子通过四面体-三角平面-八面体路径扩散,具有0.4eV的活化能和0.5eV的能量以形成八面体中间体.当它跳跃时,阳离子(Fe)分别在过渡态和四面体鞍点(亚稳态)下从+1.82的Bader电荷增加到+2.82和+2.83的电荷,这表明扩散的Fe在不同的位置具有的相应的价态.根据晶体场理论,通过八面体位置偏好能量(OSPE)是用于判断阳离子占据八面体或四面体的位置,其被定义为占据八面体和四面体的晶体场能量(CFSE)差.OSPE的顺序依次是Ni2+ > Ni3+ > Mn3+ > Fe2+ > Co3+ > Co2+ > Fe3+ > Mn2+ > Cu2+ > Zn2,由于Fe(II)、Co(II)和Ni(II)的OSPE值大于Co(III)的OSPE值,这三种阳离子在四面体可以与八面体Co(III)发生交换.对Fe(II)离子,研究发现Fe(Td)↔Co(Oh)交换很容易进行,Fe既可以占据八面体又可以占据四面体,所以FeCo2O4为复合尖晶石结构,可以从ACo2O4晶体的X射线吸收光谱法获得阳离子A的价态和分布证实.更深入研究发现尖晶石ACo2O4的晶体场,不仅决定A位阳离子的价态,同时影响这些尖晶石钴矿OER性能的关键因素.

关键词: 阳离子取代的尖晶石钴矿, 晶体场, 氧还原反应, 水分解, 电催化

Abstract: Cation substitution in spinel cobaltites (e.g., ACo2O4, in which A=Mn, Fe, Co, Ni, Cu, or Zn) is a promising strategy to precisely modulate their electronic structure/properties and thus improve the corresponding electrochemical performance for water splitting. However, the fundamental principles and mechanisms are not fully understood. This research aims to systematically investigate the effects of cation substitution in spinel cobaltites derived from mixed-metal-organic frameworks on the oxygen evolution reaction (OER). Among the obtained ACo2O4 catalysts, FeCo2O4 showed excellent OER performance with a current density of 10 mA·cm-2 at an overpotential of 164 mV in alkaline media. Both theoretical calculations and experimental results demonstrate that the Fe substitution in the crystal lattice of ACo2O4 can significantly accelerate charge transfer, thereby achieving enhanced electrochemical properties. The crystal field of spinel ACo2O4, which determines the valence states of cations A, is identified as the key factor to dictate the OER performance of these spinel cobaltites.

Key words: Cation-substituted spinel cobaltites, Crystal field, Oxygen evolution reaction, Water-splitting, Electrocatalysis