催化学报 ›› 2023, Vol. 51: 180-192.DOI: 10.1016/S1872-2067(23)64480-8

• 论文 • 上一篇    下一篇

ZnIn2S4/MOF-808微球结构S型异质结光催化剂的制备及其光还原CO2性能研究

宋明明, 宋相海, 刘鑫, 周伟强(), 霍鹏伟()   

  1. 江苏大学化学化工学院, 绿色化学与化工技术研究院, 江苏镇江212013
  • 收稿日期:2023-04-13 接受日期:2023-06-15 出版日期:2023-08-18 发布日期:2023-09-11
  • 通讯作者: *电子信箱: wqzhou@ujs.edu.cn (周伟强), huopw@ujs.edu.cn (霍鹏伟).
  • 基金资助:
    国家自然科学基金(22078131);国家自然科学基金(22108102);镇江市科技规划社会发展项目(SH2021013);江苏省青年学者基金(BK20210782);中国博士后科学基金奖学金获得者(2022M720057)

Enhancing photocatalytic CO2 reduction activity of ZnIn2S4/MOF-808 microsphere with S-scheme heterojunction by in situ synthesis method

Mingming Song, Xianghai Song, Xin Liu, Weiqiang Zhou(), Pengwei Huo()   

  1. Institute of Green Chemistry and Chemical Technology, School of Chemistry & Chemical Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu, China
  • Received:2023-04-13 Accepted:2023-06-15 Online:2023-08-18 Published:2023-09-11
  • Contact: *E-mail: wqzhou@ujs.edu.cn (W. Zhou), huopw@ujs.edu.cn (P. Huo).
  • Supported by:
    National Natural Science Foundation of China(22078131);National Natural Science Foundation of China(22108102);Science and Technology Planning Social Development Project of Zhenjiang City(SH2021013);Jiangsu Provincial Founds for Young Scholars(BK20210782);Fellowship of China Postdoctoral Science Foundation(2022M720057)

摘要:

近年来,能源过度消耗导致的温室效应引起人们广泛关注.通过不同半导体材料间能带交错排列构建异质结,用于将CO2转化为高附加值产品是解决该问题的可行方法之一.其中,S型异质结的还原型光催化剂与氧化型光催化剂具有交错带结构,使各自存在的弱空穴与弱电子复合,极大提高光生载流子的透过率和电荷利用率,有效实现强电子-空穴对分离.
在半导体中,ZnIn2S4由于能带结构适当、可见光响应范围广和化学性质稳定等优点,在CO2减排领域表现出较好的性能.但其光吸收能力低、光生载流子分离效率低和光生电子的迁移过程缓慢,这些缺点导致单一ZnIn2S4在光催化领域的应用受限.在目前半导体研究中,MOF-808制备方法简单、比表面积大以及框架结构稳定,是一种理想的催化材料.因此,本文利用MOF-808与ZnIn2S4偶联形成合适的交错带结构,构建S型异质结以提高光催化CO2还原活性.
本文采用原位合成法设计由三维花球ZnIn2S4和八面体MOF-808组成的阶跃式异质结(S型异质结).通过调控反应温度与时间设计不同尺寸的ZnIn2S4微球,并探索制备条件对光催化CO2还原活性的影响.结果表明,当ZnIn2S4微球直径为6µm时,与MOF-808偶联所构建的复合光催化剂的CO2还原活性最高.并且通过调控MOF-808比例,制备的S型异质结ZM6-15%光催化剂的CO产率在辐照4h后达到8.21μmol g‒1 h‒1,分为别MOF-808(1.03μmol g‒1 h‒1)和ZnIn2S4(0.84μmol g‒1 h‒1)的8倍和10倍左右,明显提高了光催化CO2还原性能.X射线衍射、扫描电镜、透射电镜和X射线光电子能谱(XPS)等研究结果表明,ZnIn2S4微球表面被MOF-808八面体粘附,这种紧密粘附的结构有利于ZnIn2S4与MOF-808之间载流子的转移和分离,从而提高光催化CO2的还原效果.此外,电子顺磁共振和紫外光电子能谱等测试结果表明ZnIn2S4中存在弱空穴,MOF-808中存在弱电子.在光照下,光生电子通过界面接触快速从MOF-808导带中迁移到ZnIn2S4价带中并被消耗,为光生电子提供快速传输途径,提高了电子利用率.最终,MOF-808中存在光生空穴具有最高的氧化能力,ZnIn2S4中存在光生电子具有最高的还原能力.原位XPS测试与密度泛函理论计算结果进一步证明了ZnIn2S4与MOF-808之间的S型电荷转移机制.原位红外技术分析结果表明,S型异质结ZnIn2S4/MOF-808光催化剂通过Carbene途径将CO2光催化还原为CO(CO2→CO2*→COOH*→CO*→CO).综上,本文为合理设计S型异质结光催化剂,以实现高效光催化CO2还原活性提供了新思路.

关键词: S型异质结, 形态作用, 光催化CO2还原, 光生电子与空穴, 电荷转移机制

Abstract:

The design of a heterogeneous structure for photocatalysts has attracted significant attention. In this study, a step-scheme (S-scheme) heterojunction was designed using an in-situ synthesis method. The resulting heterojunction comprised 3D microspheres of ZnIn2S4 and octahedral MOF-808 (ZnIn2S4/MOF-808). During this process, we investigated the impact of the scale of the ZnIn2S4 microspheres on performance by controlling the growth of the ZnIn2S4 microspheres with various scales. The maximum catalytic activity was discovered to be achieved with ZnIn2S4 microspheres of 6 µm when coupled with MOF-808. Compared to pure ZnIn2S4 and MOF-808, the fabricated S-scheme ZnIn2S4/MOF-808 heterojunction exhibited notably improved photocatalytic CO2 reduction performance. The performance of the CO yield of the optimized sample could reach 8.21 μmol g‒1 h‒1, which was approximately 10 and 8 times higher than those of ZnIn2S4 (0.84 μmol g‒1 h‒1) and MOF-808 (1.03 μmol g‒1 h‒1), respectively. Moreover, ultraviolet photoelectron spectroscopy, ESR, in situ X-ray photoelectron spectroscopy, and density functional theory calculations were used to study the charge transfer mechanism of the S-scheme heterojunction. In-situ FT-IR investigation established the Carbene pathway as the source of CO production (CO2 → CO2* → COOH* → CO* → CO). This study provides an efficient method for designing an S-scheme heterojunction for photocatalytic CO2 reduction.

Key words: S-scheme heterojunction, Morphological effect, Photocatalytic CO2 reduction, Photogenerated electrons and holes, Charge transfer mechanism