催化学报 ›› 2025, Vol. 74: 279-293.DOI: 10.1016/S1872-2067(25)64716-4

• 论文 • 上一篇    下一篇

Z型异质结Zn3(OH)2(V2O7)(H2O)2/V-Zn(O,S): 钒异价态与氧空位缺陷协同增强可见光催化固氮性能

张鹏坤a, 吴秦汉a, 王昊昱a, 郭东昊b,*(), 赖雨洁a, 陆东芳a,*(), 李吉庆a,*(), 林金国a,*(), 袁占辉a, 陈孝云a,*()   

  1. a福建农林大学材料科学与工程学院, 福建福州 350002
    b台湾科技大学材料科学与工程系, 台湾台北 106335
  • 收稿日期:2024-11-28 接受日期:2025-02-11 出版日期:2025-07-18 发布日期:2025-07-20
  • 通讯作者: *电子信箱: dhkuo@mail.ntust.edu.tw (郭东昊),nfuljq@163.com (李吉庆),fjldf@126.com (陆东芳),fjlinjg@126.com (林金国),fjchenxy@126.com (陈孝云).
  • 基金资助:
    国家自然科学基金(31000269);福建省自然科学基金(2021J01100);福建省林业局项目(2023TG17);福建省林业局项目(2025FKJ18)

Z-scheme heterojunction Zn3(OH)2(V2O7)(H2O)2/V-Zn(O,S) for enhanced visible-light photocatalytic N2 fixation via synergistic heterovalent vanadium states and oxygen vacancy defects

Pengkun Zhanga, Qinhan Wua, Haoyu Wanga, Dong-Hau Kuob,*(), Yujie Laia, Dongfang Lua,*(), Jiqing Lia,*(), Jinguo Lina,*(), Zhanhui Yuana, Xiaoyun Chena,*()   

  1. aCollege of Materials Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, China
    bDepartment of Materials Science and Engineering, Taiwan University of Science and Technology, Taipei 106335, Taiwan, China
  • Received:2024-11-28 Accepted:2025-02-11 Online:2025-07-18 Published:2025-07-20
  • Contact: *E-mail: dhkuo@mail.ntust.edu.tw (D. Kuo), nfuljq@163.com (J. Li), fjldf@126.com (D. Lu), fjlinjg@126.com (J. Lin), fjchenxy@126.com (X. Chen).
  • Supported by:
    National Natural Science Foundation of China(31000269);Natural Science Foundation of Fujian Province(2021J01100);Forestry Department Foundation of Fujian Province(2023TG17);Forestry Department Foundation of Fujian Province(2025FKJ18)

摘要:

NH3不仅是全球氮肥工业的重要基础原料, 亦被视为潜力巨大的氢能载体, 在农业与能源领域均具有广泛应用. 当前氨的工业生产主要依赖于高能耗的哈伯-博施法, 严重依赖化石燃料并伴随大量碳排放, 不符合可持续发展的能源战略. 开发以太阳能为驱动、在常温常压下实现的光催化固氮技术, 有望为绿色合成氨提供理想路径. 然而, N2分子中极高的N≡N键解离能(941 kJ/mol)、光生载流子的快速复合以及催化剂表面活性位点的匮乏, 均严重限制了固氮效率. 虽然构建异质结和引入缺陷等策略在一定程度上可改善光催化性能, 但如何实现电子快速传输与反应活性位点的协同优化, 仍是该领域亟待突破的关键问题.

本文通过“金属异价态-氧空位协同调控”策略, 并结合Z型异质结结构有效促进光生载流子分离的性质, 采用一步水解法制备了Zn3(OH)2(V2O7)(H2O)2/V-Zn(O,S)光催化剂(ZnVO/V-Zn(O,S)), 并通过在合成过程中添加还原剂调控氧空位浓度与异价态n(V4+)/n(V5+)的比例, 在提升光吸收性能的同时, 显著改善光生电子的分离与传输行为. 结合原位X射线光电子能谱分析, 证实了ZnVO与V-Zn(O,S)之间形成Z型异质结结构, 促进了光生载流子的定向迁移. 富含氧空位和适宜n(V4+)/n(V5+)比例的Z型异质结ZnVO/V-Zn(O,S)具有优异的可见光催化固氮活性, 在无牺牲剂的条件下, NH3的产率为301.7 μmol/(g·h), 420 nm下表观量子效率(AQE)为1.148%, 其氨产率是V-Zn(O,S)催化剂的11倍. ZnVO/V-Zn(O,S)催化剂中氧空位作为反应活性中心, 不仅促进N2分子的吸附和活化, 还能加速水分子的解离反应, 为固氮反应提供质子来源; 同时丰富的氧空位还减少了H2O和N2分子在催化剂表面活性位点的竞争吸附. ZnVO/V-Zn(O,S)催化剂中异价态钒(V4+/V5+)在固氮反应过程中充当电子传递媒介, 电子通过V4+↔V5+传递, 快速供给氮反应. Z型异质结则促进光生载流子在ZnVO和V-Zn(O,S)之间的定向迁移, 有效抑制光生电子-空穴复合, 从而协同促进光催化固氮效率.

综上所述, 本研究通过金属异价态与氧空位的协同调控, 实现了Z型异质结光催化固氮活性显著提升, 提出了一种可兼顾光生电子高效利用与表面活化能力的新型材料构筑策略, 为高效光催化固氮催化剂的设计提供了理论依据和实践路径, 在绿色合成氨与清洁能源转化等领域具有广阔的应用前景.

关键词: Zn3(OH)2(V2O7)(H2O)2, Z型异质结, 金属异价态, 氧空位, 光催化固氮

Abstract:

Herein, we established a Zn3(OH)2(V2O7)(H2O)2/V-Zn(O,S) Z-scheme heterojunction (labeled ZnVO/V-Zn(O,S) with a heterovalent V4+/V5+ states and oxygen vacancies in both phases via a one-step in-situ hydrolysis method. The NaBH4 regulated the ZnVO/V-Zn(O,S)-3 with rich Vo and suitable n(V4+)/n(V5+) ratio achieved an excellent photocatalytic nitrogen fixation activity of 301.7 μmol/(g•h) and apparent quantum efficiency of 1.148% at 420 nm without any sacrificial agent, which is 11 times than that of V-Zn(O,S). The Vo acts as the active site to trap and activate N2 molecules and to trap and activate H2O to produce the H for N2 molecules photocatalytic reduction. The rich Vo defects can also reduce the competitive adsorption of H2O and N2 molecules on the surface active site of the catalyst. The heterovalent vanadium states act as the photogenerated electrons, quickly hopping between V4+ and V5+ to transfer for the photocatalytic N2 reduction reaction. Additionally, the Z-scheme heterojunction effectively minimizes photogenerated carrier recombination. These synergistic effects collectively boost the photocatalytic nitrogen fixation activity. This study provides a practical method for designing Z-scheme heterojunctions for efficient photocatalytic N2 fixation under mild conditions.

Key words: Zn3(OH)2(V2O7)(H2O)2, Z-scheme heterojunction, Heterovalent valence states, Oxygen vacancy, Photocatalytic N2 fixation