催化学报 ›› 2024, Vol. 58: 180-193.DOI: 10.1016/S1872-2067(23)64609-1

• 论文 • 上一篇    下一篇

由质子化D-A型聚合物和MoS2构建S型异质结实现高效光催化析氢

潘劲康a,b,1, 张艾彩珺a,b,1, 张莉华a,c, 董鹏玉a,*()   

  1. a盐城工学院, 江苏省新型环保重点实验室, 江苏盐城224051
    b盐城工学院化学化工学院, 江苏盐城224051
    c盐城工学院机械工程学院, 江苏盐城224051
  • 收稿日期:2023-11-30 接受日期:2024-01-21 出版日期:2024-03-18 发布日期:2024-03-28
  • 通讯作者: *电子信箱: dongpy11@gmail.com (董鹏玉).
  • 作者简介:1共同第一作者.
  • 基金资助:
    国家自然科学基金(21403184);盐城工学院分析测试中心支持.;江苏省高等学校基础科学(自然科学)研究重大项目(22KJA430008)

Construction of S-scheme heterojunction from protonated D-A typed polymer and MoS2 for efficient photocatalytic H2 production

Jinkang Pana,b,1, Aicaijun Zhanga,b,1, Lihua Zhanga,c, Pengyu Donga,*()   

  1. aKey Laboratory for Advanced Technology in Environmental Protection of Jiangsu Province, Yancheng Institute of Technology, Yancheng 224051, Jiangsu, China
    bSchool of Chemistry and Chemical Engineering, Yancheng Institute of Technology, Yancheng 224051, Jiangsu, China
    cSchool of Mechanical Engineering, Yancheng Institute of Technology, Yancheng 224051, Jiangsu, China
  • Received:2023-11-30 Accepted:2024-01-21 Online:2024-03-18 Published:2024-03-28
  • Contact: *E-mail: dongpy11@gmail.com (P. Dong).
  • About author:1Contributed equally to this work.
  • Supported by:
    National Natural Science Foundation of China(21403184);and the support of the Analysis & Testing Center of Yancheng Institute of Technology.;Qinglan Project of Jiangsu Province of China, the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(22KJA430008)

摘要:

化石能源的过度消耗及其所引发的环境污染已经成为制约人类社会可持续发展的关键因素, 因此开发绿色、可再生的能源已成为全球的迫切需求. 氢能作为一种新型能源, 具有能量密度高、清洁以及可持续等优点, 备受研究者的关注. 光催化分解水制氢技术能够将太阳能转化为可储存的清洁能源, 被视为未来解决能源和环境问题的可行性方案. 在过去几十年里, 众多科学家致力于研发各种高效的析氢光催化剂, 以推进光催化分解水制氢技术的实际应用. 其中, S型异质结光催化剂因其快速的光生电荷转移效率和出色的氧化还原能力, 被认为是提高光催化析氢性能的有效途径之一.

本文以质子化、具有供体-受体(D-A)构型的PyDTDO-3共轭聚合物和二维层状MoS2为原料, 构建了一种S型异质结(PPMS), 并将其用于光催化分解水制氢. 红外光谱结果表明, 质子化处理导致PyDTDO-3表面吸附了大量H+, 使其Zeta电势降低, 表面负电荷减少, 更有利于MoS2的吸附, 进而形成具有紧密接触界面的PPMS S型异质结. 在可见光照射下, PPMS-0.5%(即MoS2占PyDTDO-3的质量百分数为0.5%)S型异质结的性能最佳, 其光催化析氢效率达到75.4 mmol g-1 h-1, 是纯PyDTDO-3的4.6倍. 此外, 在550 nm光激发下, PPMS-0.5%异质结的光催化析氢表观量子效率最高达到19.6%. 光电流响应和电化学阻抗谱结果表明, PPMS异质结展现出了显著提升的光生电荷分离效率. 通过密度泛函理论计算发现, PyDTDO-3和MoS2具有不同的功函数, 这导致费米能级间隙的产生, 从而形成了内建电场. 该内建电场有助于MoS2上的电子自发转移到PyDTDO-3上, 从而在PyDTDO-3与MoS2的界面上产生了明显的差分电荷密度分布: PyDTDO-3表面带有负电荷, MoS2表面则带有正电荷. 在可见光激发下, 得益于PyDTDO-3独特的D-A型结构, 光生电子可以快速从供体(芘供体)的最高占据分子轨道传递到受体(DTDO受体)的最低未占据分子轨道(LUMO); 随后, 这些被激发的光生电子进入MoS2的表面. 利用飞秒瞬态吸收光谱研究动力学行为, 结果表明, 来自PyDTDO-3的LUMO电子转移加速了MoS2价带的空穴消耗, 这进一步证实了S型光生电荷分离机制. 此外, 与单组分PyDTDO-3和MoS2相比, PPMS S型异质结具有较低的吉布斯自由能(ΔGH*, 0.77 eV), 表明它更有利于过渡态(H*)的形成以及分子氢在PPMS上的有效解吸. 总之, PPMS S型异质结表现出促进的电荷定向迁移和增加的活性位点, 共同增强了其光催化析氢性能.

综上, 本文首先对D-A构型的PyDTDO-3进行质子化处理, 再与MoS2复合, 制备了具有紧密接触界面的S型PPMS异质结. 该异质结结构显著促进了PyDTDO-3和MoS2之间的电荷定向迁移; 此外, 通过引入MoS2中丰富的S原子, 增加了光催化析氢活性位点, 从而大大提高了光催化析氢效率. 本文为设计和开发新型高效的光催化析氢材料提供了新的思路和参考.

关键词: S型异质结, 质子化D-A型聚合物, MoS2, 光催化析氢, 密度泛函理论计算

Abstract:

This study involves a heterojunction (denoted as PPMS) with an intimate heterointerface and S-scheme architecture, which consisted of a conjugated polymer of protonated PyDTDO-3 featuring a donor-acceptor (D-A) configuration and a 2D-layered MoS2. The optimal PPMS-0.5% heterojunction exhibits a remarkable efficiency of 75.4 mmol g‒1 h-1 in generating H2 when subjected to visible light illumination, representing an approximately 4.6 times enhancement compared to pure PyDTDO-3. To elucidate the photocatalytic mechanism, a range of characterization methods were utilized and calculations using density functional theory were carried out. The disparity in the work function between PyDTDO-3 and MoS2 results in the creation of a Fermi-level gap. Consequently, the establishment of a built-in electric field facilitates the occurrence of the electrons in MoS2 spontaneously transferring to PyDTDO-3 at the interface. The consumption of hole on the valence band of MoS2 is accelerated by the electron transfer from the lowest unoccupied molecular orbital (LUMO) of PyDTDO-3, according to a kinetic study using femtosecond transient absorption spectra (fs-TAS). Moreover, the S-scheme PPMS exhibits a lower Gibbs free energy (ΔGH*, 0.77 eV) in comparison to the individual component, indicating it facilitates the formation of the transitional state (H*) and the effective desorption of molecular hydrogen on PPMS. Both the promoting directed charge migration and the increasing active sites contribute to the boosted photocatalytic H2 evolution.

Key words: S-Scheme heterojunction, Protonated D-A typed polymer, MoS2, Photocatalytic hydrogen evolution, Density functional theory calculation