催化学报

催化学报 ›› 2026, Vol. 83: 172-182.DOI: 10.1016/S1872-2067(25)64895-9

• 论文 • 上一篇    下一篇

(CuGa)xZn1-2xGa2S4半导体材料的表面电子结构调控及其光催化还原硝酸盐制氨性能

刘彭a, 段炼a, 杨宝鹏b, 孙铭伟a, 陈根a, 刘小鹤c, 刘敏b,*(), 张宁a,*()   

  1. a中南大学材料科学与工程学院, 湖南长沙 410083
    b中南大学物理学院, 湖南长沙 410083
    c郑州大学化工学院, 河南郑州 450001
  • 收稿日期:2025-08-02 接受日期:2025-08-31 出版日期:2026-04-18 发布日期:2026-03-04
  • 通讯作者: * 电子信箱: nzhang@csu.edu.cn (张宁), minliu@csu.edu.cn (刘敏).
  • 基金资助:
    国家自然科学基金(22072183);国家自然科学基金(22376222);湖南省自然科学基金(2022JJ30690);湖南省科技创新领军人才项目(2023RC1012);中南大学前沿交叉项目(2023QYJC012)

Tuning surface electronic structure of (CuGa)xZn1‒2xGa2S4 photocatalyst for efficient nitrate-to-ammonia conversion

Peng Liua, Lian Duana, Baopeng Yangb, Mingwei Suna, Gen Chena, Xiaohe Liuc, Min Liub,*(), Ning Zhanga,*()   

  1. aSchool of Materials Science and Engineering, Central South University, Changsha 410083, Hunan, China
    bSchool of Physics, Central South University, Changsha 410083, Hunan, China
    cSchool of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, Henan, China
  • Received:2025-08-02 Accepted:2025-08-31 Online:2026-04-18 Published:2026-03-04
  • Contact: * E-mail: nzhang@csu.edu.cn (N. Zhang), minliu@csu.edu.cn (M. Liu).
  • Supported by:
    National Natural Science Foundation of China(22072183);National Natural Science Foundation of China(22376222);Natural Science Foundation of Hunan Province, China(2022JJ30690);Science and Technology lnnovation Program of Hunan Province(2023RC1012);Central South University Research Program of Advanced Interdisciplinary Studies(2023QYJC012)

RichHTML

3

PDF

32

摘要：

环境中过量的硝酸盐(NO3-)污染对生态系统和人类健康构成了严重威胁. 在温和条件下将NO3-选择性地光催化还原为高价值的氨(NH3), 是修复氮循环平衡的理想途径. 该过程的关键在于NO3-及其中间体在催化剂表面的吸附与活化, 而这一过程深受催化剂表面电子结构, 特别是d带中心位置的影响. 然而, 传统的电子结构调控策略(如体相掺杂或构建异质结)往往会显著改变整体能带结构, 从而降低光催化性能. 因此, 在不破坏本征能带结构的前提下精准调控催化剂表面d带电子态, 对构筑高效硝酸盐还原光催化剂具有重要意义.
本文采用简便的离子交换法, 将不同比例的Al3+表面修饰于(CuGa)xZn1‒2xGa2S4硫化物半导体表面, 旨在精准调控其d带中心而不改变导带和带隙结构, 从而增强对NO3-的吸附与活化. 电感耦合等离子体发射光谱和X-射线光电子能谱(XPS)等结果证实了Al3+的成功引入及其表面富集特性(表面含量约1.03 at%). X射线衍射与电子显微镜分析结果表明, Al3+修饰未改变材料的晶体结构和基本形貌. X-射线吸收精细结构分析显示, Zn-S键长发生了明显变化, 说明表面局部电子结构得到有效调控. 光学性质研究结果表明, 改性后的材料保持了对可见光的良好吸收能力, 带隙仅发生微小变化(从2.57 eV变为2.54 eV), 导带底位置维持在约-1.9 V (vs. RHE)的强还原电位. 高分辨率XPS价带谱显示, Al3+修饰使材料的d带中心从-3.06 eV上移至-2.85 eV, 更接近费米能级. 时间分辨荧光光谱显示, 改性后材料的载流子寿命从1.59 ns延长至2.52 ns, 表明表面修饰有效抑制了载流子复合. 光催化性能测试表明, Al3+修饰显著提升了硝酸盐还原性能. 其中, Al3+/(CuGa)xZn1-2xGa2S4-0.01%材料的产氨速率高达0.93 mmol h-1 g-1, 是原始材料(0.18 mmol h-1 g-1)的5.17倍, 同时NH4+选择性从56.17%显著提升至72.16%. 副产物分析表明, H2产率同步增加, CO2检测证实了牺牲剂乙二醇的有效氧化. 通过离子色谱和核磁共振等多种手段证实了氨产物的生成与定量准确性, 循环实验证明催化剂具有良好的稳定性(60 h测试后活性保持良好). 机理研究表明, NO3-的逐步还原路径为: (*+NO3-) → *NO3 → *NO2 → *NO → *NOH → *NHOH → *NH2OH → *NH2 → *NH3 → NH3. 密度泛函理论计算进一步揭示, d带中心的上移优化了反应中间体在Zn活性位点上的吸附行为, 并将速率决定步骤(*NO2 → *NO)的吉布斯自由能垒从1.51 eV降低至0.90 eV, 从而显著促进了反应动力学.
综上, 本工作不仅构建了一种高效光催化硝酸盐还原制氨材料, 还提出了一种通过表面修饰精准调控d带中心而不改变本征能带结构的策略. 这为设计高性能, 高选择性的环境催化与能源转化材料提供了新的思路和理论依据.

关键词: 光催化, 电子结构, d带中心, 硫化物, 硝酸盐还原

Abstract:

The photocatalytic conversion of nitrate (NO3-) into ammonia (NH4+) under mild conditions offers a promising approach for mitigating environmental nitrate contamination. The efficiency of this process is fundamentally governed by the adsorption and activation of NO3- and its intermediates, which are significantly influenced by the surface electronic properties of the catalyst, particularly the position of the d-band center. However, conventional approaches to tune the surface electronic structure such as doping with extraneous elements or forming heterojunctions often alter the overall band structure seriously, typically leading to reduced photocatalytic activity. In this study, the d-band state of (CuGa)xZn1‒2xGa2S4 semiconductor is engineered through Al3+ surface decoration without affecting the conduction band or the bandgap to enhance NO3- adsorption and activation. X-ray photoelectron spectroscopy and X-ray absorption fine structure analyses reveal that the surface doping of Al3+ do not induce obviously energy band structure change but the d-band center, which shift more closer to Fermi level in comparison with pristine material. Electronic energy band analyses indicate that Al3+ decoration does not significantly alter the conduction band or bandgap. Moreover, the Al3+-modified material demonstrates a substantial improvement in photocatalytic conversion of NO3- into NH4+, increasing the NH4+ production rate from 0.18 to 0.93 mmol h-1 g-1. Density functional theory calculations further revealed that the d-band center of Al3+/(CuGa)xZn1-2xGa2S4 shifted closer to the Fermi level, moving from -4.75 to -4.54 eV compared to the pristine (CuGa)xZn1-2xGa2S4. This shift lowered the Gibbs free energy for the adsorption of NO3- reduction intermediates, thereby enhancing the conversion efficiency of NO3- into NH4+. This work introduces an effective strategy for surface d-band states modulation without altering the intrinsic band structure to improve nitrate reduction performance, offering deep insights into the future design of materials for environmental remediation applications.

Key words: Photocatalysis, Electronic structure, d-band center, Sulfide, Nitrate reduction