催化学报 ›› 2022, Vol. 43 ›› Issue (2): 276-287.DOI: 10.1016/S1872-2067(21)63817-2

• 论文 • 上一篇    下一篇

BiOBr/Ni2P/g-C3N4体系中用Ni2P电子桥加速S型体系光生载流子分离

陈男男a, 贾雪梅a, 何恒a, 林海莉a,*(), 郭敏娜a, 曹静a, 张金锋b, 陈士夫a,#()   

  1. a淮北师范大学化学与材料科学学院, 绿色和精准合成化学及应用教育部重点实验室, 安徽淮北 235000
    b淮北师范大学物理与电子信息学院, 安徽淮北 235000
  • 收稿日期:2021-01-31 接受日期:2021-03-28 出版日期:2022-02-18 发布日期:2021-05-20
  • 通讯作者: 林海莉,陈士夫
  • 基金资助:
    国家自然科学基金(21902056);国家自然科学基金(51972134);国家自然科学基金(51772118);国家自然科学基金(51973078);安徽省自然科学基金(1908085MB36)

Promoting photocarriers separation in S-scheme system with Ni2P electron bridge: The case study of BiOBr/Ni2P/g-C3N4

Nannan Chena, Xuemei Jiaa, Heng Hea, Haili Lina,*(), Minna Guoa, Jing Caoa, Jinfeng Zhangb, Shifu Chena,#()   

  1. aKey Laboratory of Green and Precise Synthetic Chemistry and Applications, Ministry of Education, College of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, Anhui, China
    bCollege of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000, Anhui, China
  • Received:2021-01-31 Accepted:2021-03-28 Online:2022-02-18 Published:2021-05-20
  • Contact: Haili Lin, Shifu Chen
  • Supported by:
    This work was supported by the National Natural Science Foundation of China(21902056);This work was supported by the National Natural Science Foundation of China(51972134);This work was supported by the National Natural Science Foundation of China(51772118);This work was supported by the National Natural Science Foundation of China(51973078);the Natural Science Foundation of Anhui Province(1908085MB36)

摘要:

水污染对人类健康和生态环境造成了严重的危害, 引起了人们广泛关注. 半导体光催化技术被认为是一种去除废水中有机污染物的有效方法. 近年来, 石墨相氮化碳(g-C3N4)作为一种无金属的光催化剂, 具有合适的带隙能(Eg ≈ 2.7 eV)、良好的化学稳定性、较好的热稳定性、无毒以及强的还原电位(ECB ≈ -1.3 eV)等特点, 表现出较好的光催化活性. 但由于g-C3N4光生载流子复合快和量子效率低, 限制了其实际应用. 因此, 研究者们开发了各种有效的方法来克服上述缺点, 如调控形貌、掺杂离子、沉积贵金属和构建异质结等. 其中, 构建梯型(S型)异质结已被证实是提高复合材料光催化活性的一种有效策略. S型异质结的形成不仅有效地加速光生电子和空穴的分离和迁移, 而且还增强了光生载流子的氧化还原能力. 除了电子结构外, 异质结的界面电阻直接影响着光生载流子的分离效率, 从而决定光催化活性强弱. 据报道, 具有高导电性的“电子传递介质”或“电子桥”可有效地降低载流子迁移过程中的界面阻力. 过渡金属磷化物具有优良的导电性、低廉的价格和无毒的特性, 完全满足电子桥的要求, 成为电子桥的最佳候选材料之一.
结合S型异质结和电子桥的优势, 本文采用沉积-沉淀法制备了一种新型的S型BiOBr/Ni2P/g-C3N4异质结. 在可见光(λ ≥ 400 nm)下, 该催化剂对甲基橙和罗丹明B的降解活性明显优越于BiOBr/g-C3N4. 这主要归因于电子桥Ni2P和S型异质结的协同效应. 密度泛函理论计算表明, 电子从BiOBr通过电子桥Ni2P转移到g-C3N4. 在可见光照射下以及界面内建电场的驱动下, 带边缘弯曲和库仑相互作用协同促进了复合物中相对无用的电子和空穴的重组, 从而保留了较强氧化还原能力的电子和空穴. 活性氧捕获实验、电子顺磁共振光谱和电流-电压曲线结果进一步证明, 光催化剂中的电荷迁移方式遵循S型异质结的迁移机制. 综上, 本文不仅为S型光催化剂的设计提供了有效策略, 也为界面载流子的快速分离和迁移提供了切实可行的途径.

关键词: BiOBr/Ni2P/g-C3N4, S模式, 界面电子迁移, 电子桥, 光催化剂

Abstract:

Constructing step-scheme (S-scheme) heterojunctions can considerably facilitate separation and transfer of photocarriers, as well as promote strong redox ability. The interface resistance of heterojunctions immediately affects photocarrier separation and determines the photocatalytic activity. Herein, we constructed a novel BiOBr/Ni2P/g-C3N4 heterojunction using Ni2P as a novel electron bridge to reduce the interfacial resistance of photocarriers between BiOBr and g-C3N4. The as-prepared 10% BiOBr/Ni2P/g-C3N4 sample exhibited outstanding visible-light photocatalytic performance for methyl orange and rhodamine B removal, with degradation efficiencies of 91.4% and 98.9%, respectively. The excellent photocatalytic activity of BiOBr/Ni2P/g-C3N4 was mainly attributed to the synergistic effects of the Ni2P cocatalyst and S-scheme heterojunction, which not only reduced the interface resistance but also retained the strong redox potential of the photocarriers. In addition, the formation of the S-scheme system was supported by active oxygen species investigation, current-voltage curves, and density functional theory calculations. This work provides a guideline for the design of highly efficient S-scheme photocatalysts with transition metal phosphates as electron bridges to improve photocarriers separation.

Key words: BiOBr/Ni2P/g-C3N4, S-scheme, Interfacial electron transfer, Electron-bridge, Photocatalysis