物理化学学报 >> 2022, Vol. 38 >> Issue (7): 2112037.doi: 10.3866/PKU.WHXB202112037

所属专题: 异质结光催化材料

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反蛋白石结构ZnO@PDA用于增强光催化产H2O2性能

韩高伟1, 徐飞燕2, 程蓓1, 李佑稷3, 余家国2, 张留洋2,*()   

  1. 1 武汉理工大学,材料复合新技术国家重点实验室,武汉 430070
    2 中国地质大学(武汉),材化学院太阳燃料实验室,武汉 430074
    3 吉首大学,化学与化工学院,湖南 吉首 416000
  • 收稿日期:2021-12-29 录用日期:2022-01-14 发布日期:2022-01-19
  • 通讯作者: 张留洋 E-mail:zhangliuyang@cug.edu.cn
  • 基金资助:
    国家自然科学基金(52073223);国家自然科学基金(51872220);国家自然科学基金(51932007);国家自然科学基金(51961135303);国家自然科学基金(21871217);国家自然科学基金(U1905215)

Enhanced Photocatalytic H2O2 Production over Inverse Opal ZnO@Polydopamine S-Scheme Heterojunctions

Gaowei Han1, Feiyan Xu2, Bei Cheng1, Youji Li3, Jiaguo Yu2, Liuyang Zhang2,*()   

  1. 1 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
    2 Laboratory of Solar Fuel, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
    3 College of chemistry and Chemical engineering, Jishou University, Jishou 416000, Hunan Province, China
  • Received:2021-12-29 Accepted:2022-01-14 Published:2022-01-19
  • Contact: Liuyang Zhang E-mail:zhangliuyang@cug.edu.cn
  • About author:Liuyang Zhang, Email: zhangliuyang@cug.edu.cn; Tel: +86-27-65277083
  • Supported by:
    the National Natural Science Foundation of China(52073223);the National Natural Science Foundation of China(51872220);the National Natural Science Foundation of China(51932007);the National Natural Science Foundation of China(51961135303);the National Natural Science Foundation of China(21871217);the National Natural Science Foundation of China(U1905215)

摘要:

利用太阳能驱动生产高能量密度的H2O2太阳能燃料引起了广泛关注,但目前光催化剂缓慢的动力学限制了其实际应用。本文制备一种聚多巴胺(PDA)改性的反蛋白石结构ZnO(ZnO@PDA)光催化剂,用于可持续性的光催化产H2O2。由于电子的转移,因此当PDA与ZnO接触后,会在界面处形成一个从PDA指向ZnO的内建电场。在内建电场和能带弯曲的驱动下,ZnO导带中的光生电子与PDA最高占据分子轨道(HOMO)中的空穴复合,符合梯型异质结的电荷转移和分离途径。这种独特的梯型异质结确保了有效的电子或空穴的分离并且留存下具有强氧化还原能力的光生载流子。此外,与纯ZnO相比,反蛋白石结构的ZnO@PDA具有更强的光吸收能力。实验表明,归因于光吸收能力的提高,光生载流子的有效分离和强氧化还原能力,负载0.03% (原子分数) PDA的ZnO样品具有最佳的产H2O2性能(1011.4 μmol·L-1·h-1),分别是纯ZnO和PDA的4.4和8.9倍。

关键词: S型异质结, 聚多巴胺, ZnO反蛋白石结构, 光催化产H2O2

Abstract:

Photocatalytic H2O2 production is a sustainable and inexpensive process that requires water and gaseous O2 as raw materials and sunlight as the energy source. However, the slow kinetics of current photocatalysts limits its practical application. ZnO is commonly used as a photocatalytic material in the solar-to-chemical conversion, owing to its high electron mobility, nontoxicity, and relatively low cost. The adsorption capacity of H2O2 on the ZnO surface is low, which leads to the continuous production of H2O2. However, its photoresponse is limited to the ultraviolet (UV) region due to its wide bandgap (3.2 eV). Polydopamine (PDA) has emerged as an effective surface functionalization material in the field of photocatalysis due to its abundant functional groups. PDA can be strongly anchored onto the surface of a semiconducting photocatalyst through covalent and noncovalent bonds. The superior properties of PDA served as a motivation for this study. Herein, we prepare an inverse opal-structured porous PDA-modified ZnO (ZnO@PDA) photocatalyst by in situ self-polymerization of dopamine hydrochloride. The crystal structure, morphology, valency, stability, and energy band structure of photocatalysts are characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), electrochemical impedance spectroscopy (EIS), Mott-Schottky curve (MS), and electron paramagnetic resonance (EPR). The experimental results showed that electrons in PDA are transferred to ZnO upon contact, which results in an electric field at their interface in the direction from PDA to ZnO. The photoexcited electrons in the ZnO conduction bands flow into PDA, driven by the electric field and bent bands, and are recombined with the holes of the highest occupied molecular orbital of PDA, thereby exhibiting an S-scheme charge transfer. This unique S-scheme mechanism ensures effective electron/hole separation and preserves the strong redox ability of used photocarriers. In addition, the inverse opal structure of ZnO@PDA promotes light-harvesting due to the supposed "slow photon" effect, as well as Bragg diffraction and scattering. Moreover, the enhanced surface area provides a high adsorption capacity and increased active sites for photocatalytic reactions. Therefore, the resulting ZnO@PDA (0.03% (atomic fraction) PDA) exhibits the optimal H2O2 production performance (1011.4 μmol·L-1·h-1), which is 4.4 and 8.9 times higher than pristine ZnO and PDA, respectively. The enhanced performance is ascribed to the improved light absorption, efficient charge separation, and strong redox capability of photocarriers in the S-scheme heterojunction. Therefore, this study provides a novel strategy for the design of inorganic/organic S-scheme heterojunctions for efficient photocatalytic H2O2 production.

Key words: Step-scheme heterojunction, Polydopamine, Inverse opal ZnO, Photocatalytic H2O2 production

MSC2000: 

  • O643