应用化学 ›› 2024, Vol. 41 ›› Issue (7): 1010-1023.DOI: 10.19894/j.issn.1000-0518.240031

• 研究论文 • 上一篇    下一篇

窄带隙 β-CuFeO2铁电光催化剂性质及表面析氧反应特性

吕东昊1,2, 徐兰兰1, 刘孝娟1,2()   

  1. 1.中国科学院长春应用化学研究所,稀土资源利用国家重点实验室,长春 130022
    2.中国科学技术大学,合肥 230026
  • 收稿日期:2024-01-30 接受日期:2024-05-07 出版日期:2024-07-01 发布日期:2024-08-03
  • 通讯作者: 刘孝娟
  • 基金资助:
    国家自然科学基金(U2130114);吉林省自然科学基金项目(YDZJ202201ZYS378)

The Properties of Narrow Bandgap β-CuFeO2 Ferroelectric Photocatalysts and Surface Oxygen Evolution Reaction Characteristics

Dong-Hao LYU1,2, Lan-Lan XU1, Xiao-Juan LIU1,2()   

  1. 1.State Key Laboratory of Rare Earth Resources Utilization,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022,China
    2.University of Science and Technology of China,Hefei 230026,China
  • Received:2024-01-30 Accepted:2024-05-07 Published:2024-07-01 Online:2024-08-03
  • Contact: Xiao-Juan LIU
  • About author:lxjuan@ciac.ac.cn
  • Supported by:
    the National Natural Science Foundation of China(U2130114);the Natural Science Foundation of Jilin Province(YDZJ202201ZYS378)

摘要:

铜铁矿(delafossite)型CuFeO2具有窄带隙、良好稳定性被广泛用于光催化领域的研究,而其中心对称的层状结构使得光生载流子容易复合,限制了其光催化效果。 β-CuFeO2是一种具有相稳定,窄带隙,强极化的本征铁电半导体,利用其内禀的铁电极化性质,构建光生电子空穴生成位点交替排列的[011]表面,在铁电内建电场作用下促进电荷分离,从而提升光催化性能。 基于第一性原理计算,本文首先确定β-CuFeO2具有热力学稳定性,磁基态为C型反铁磁,且带隙为1.37 eV的直接带隙半导体,理论铁电极化为83.466 μC/cm2,是良好的光催化剂载体。 进一步地,以表面析氧反应(OER)为模型,通过构建非极化表面[100]、[010]和极化表面[001]、[011]研究铁电极化对OER的影响。 结果表明,β-CuFeO2的表面价带顶氧化还原电势大部分大于水氧化电势(1.23 eV),且极化表面更易形成。 此外,在极化方向上,完全暴露Cu-O原子,Cu,Fe原子层交替排列的[011]表面最易吸附水分子且具有最优OER催化活性。 对[011]表面OER决速步骤进行电子结构分析,发现在*O中间体上具有2个电子口袋,反应生成*OOH后消耗一个电子口袋,即空轨道上得到电子。 这是[011]极化方向表面OER决速步骤的内在机理。 本工作构建了β-CuFeO2铁电半导体并通过理论模拟计算了其基本性质,构建了不同方向表面研究铁电极化对光催化OER活性的影响,将为铁电光催化剂设计提供理论依据。

关键词: β-CuFeO2, 第一性原理计算, 密度泛函理论, 光催化, 析氧反应, 铁电极化

Abstract:

Delafossite CuFeO2 is widely used in the field of photocatalysis due to its narrow band gap and easy availability, while the photogenerated carriers are easy to compound due to its centrosymmetric layered structure, limiting its photocatalytic effect. In view of this, this paper focuses on another configuration of CuFeO2, namely β-CuFeO2, which is an intrinsic ferroelectric semiconductor with phase stability, narrow band gap, and strong polarization. We construct the [011] surface with alternating arrangement of photogenerated electron and hole generation sites, which promotes charges separation under the action of ferroelectric built-in electric field to enhance the photocatalytic performance. Based on first-principles calculations, this study identified β-CuFeO2 as a direct bandgap semiconductor with thermodynamic stability, a C-type antiferromagnetism in the magnetic ground state, and the bandgap size of 1.37 eV, with a theoretical ferroelectric polarization intensity of 83.46 μC/cm2, which is a good photocatalyst carrier. Further, using the surface oxygen precipitation reaction (OER) as a model, unpolarized direction surfaces [100], [010] and polarized direction surfaces [001], [011] were constructed to investigate the effect of ferroelectric polarization on the OER. The results show that the surface Valance Band Maximum (VBM) redox potential of β-CuFeO2 is mostly more than the water oxidation potential (1.23 eV) and the polarized surface is easier to form. In addition, the [011] surface with fully exposed Cu-O atoms and alternating layers of Cu, Fe atoms in the polarization direction is the most susceptible to adsorption of water molecules and has the optimal OER catalytic activity. The electronic structure analysis of the rate-determining step for the OER on the [011] surface reveals that there are two electron pockets on the *O intermediate, and one electron pocket is consumed after the reaction to produce *OOH. This is the intrinsic mechanism of the OER rate-determining step on the polarization direction [011] surface. β?-CuFeO2 ferroelectric semiconductor was constructed in this work and its basic properties were calculated by theoretical simulations, and different directions of surfaces were constructed to study the effect of ferroelectric polarization on the photocatalytic OER activity, which will provide a new perspective for the design of ferroelectric photocatalysts.

Key words: β?-CuFeO2, First-principles calculation, DFT, Photocatalysts, Oxygen evolution reaction, Ferroelectric polarization

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