物理化学学报 >> 2024, Vol. 40 >> Issue (10): 2309020.doi: 10.3866/PKU.WHXB202309020

所属专题: 太阳燃料光催化剂

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Ti3C2/In4SnS8肖特基异质结用于高效光催化生成H2O2和Cr(Ⅵ)还原

周彤1,†, 刘雪2,†, 赵亮1, 乔明涛1, 雷琬莹1,*()   

  1. 1 西安建筑科技大学材料科学与工程学院, 西安 710055
    2 中国农业科学院烟草研究所, 山东 青岛 266101
  • 收稿日期:2023-09-12 修回日期:2023-10-18 录用日期:2023-10-19 发布日期:2024-03-13
  • 通讯作者: Email: leiwy@xauat.edu.cn (雷琬莹)
  • 作者简介:

    †These authors contributed equally to this work.

  • 基金资助:
    国家自然科学基金(51902243); 国家自然科学基金(52302112); 陕西省教育厅重点科研计划项目(22JY039); 陕西省教育厅重点科研计划项目(22JY037); 中央非营利科研机构基础研究经费(1610232023008); 农业科技创新计划(ASTIP-TRIC07)

Efficient Photocatalytic H2O2 Production and Cr(Ⅵ) Reduction over a Hierarchical Ti3C2/In4SnS8 Schottky Junction

Tong Zhou1, Xue Liu2, Liang Zhao1, Mingtao Qiao1, Wanying Lei1,*()   

  1. 1 College of Materials and Science, Xi'an University of Architecture and Technology, Xi'an 710055, China
    2 Institute of Tobacco Research, Chinese Academy of Agricultural Sciences, Qingdao 266101, Shandong Province, China
  • Received:2023-09-12 Revised:2023-10-18 Accepted:2023-10-19 Published:2024-03-13
  • Contact: Email: leiwy@xauat.edu.cn (Wanying Lei)
  • Supported by:
    the National Natural Science Foundation of China(51902243); the National Natural Science Foundation of China(52302112); Key Research Project of Shaanxi Education Department(22JY039); Key Research Project of Shaanxi Education Department(22JY037); the Fundamental Research Funds for Central Non-Profit Scientific Institution(1610232023008); the Agricultural Science and Technology Innovation Program(ASTIP-TRIC07)

摘要:

人工光合成是一种先进的技术,可以利用太阳能作为唯一驱动能源,将水和氧气转化成双氧水(H2O2)。然而,目前常用的光催化体系的性能受制于其光吸收能力有限,载流子分离效率低以及表面反应能力弱等问题。在本文研究中,采用原位水热法,成功地在少层Ti3C2片表面生长厚度为5–10 nm的立方相In4SnS8 nm片(Eg = 2.16 eV),形成了一种具有三明治结构的Ti3C2/In4SnS8纳米复合材料。Ti3C2和In4SnS8之间较大的界面面积及紧密的界面接触有助于载流子在体系中的迁移。X射线衍射仪(XRD)、透射电子显微镜(TEM),和X射线光电子能谱(XPS)证实了Ti3C2/In4SnS8纳米复合材料的成功构建。能带结构包括价带顶端和Mott-Schottky曲线表明此2D/2D异质结形成了肖特基异质结,有助于载流子的快速分离,并从In4SnS8转移至Ti3C2表面,避免了电子从Ti3C2回流至In4SnS8。荧光光谱分析和光/电测试结果证明了Ti3C2和In4SnS8的复合有效抑制了载流子的复合。其中,7 wt% Ti3C2/In4SnS8复合材料表现出最佳的可见光催化性能,H2O2生成速率为1.998 µmol∙L−1∙min‒1,比单独In4SnS8高2.2倍。此外,Ti3C2/In4SnS8表现出多功能应用,对Cr(Ⅵ)的还原速率为19.8 × 10−3 min‒1,比单一In4SnS8性能高约4倍。Ti3C2/In4SnS8复合材料在经过五次循环实验测试后表现优异的稳定性,其形貌、晶体结构和组成在反应后未发生改变。通过深层次的分析包括捕获实验、气氛实验和电子顺磁共振,证明了H2O2生成的途径包括两种:一种是两步单电子还原路径,另一种是一步两电子水氧化路径。本研究为设计高效、多功能的催化体系提供了一种新的思路。

关键词: Ti3C2, In4SnS8, 光催化, 生成H2O2, Cr(Ⅵ)还原

Abstract:

Artificial photosynthesis is an appealing approach for generating hydrogen peroxide (H2O2) from H2O and O2 with solar energy as the sole energy input. However, the current catalyst systems commonly face challenges such as the limited optical absorption, poor electron-hole pair separation efficiency, and restricted surface reactivity, which hinders the overall photoactivity. Here, we immobilize cubic-phase ultrathin In4SnS8 nanosheets (Eg = 2.16 eV) with thickness of 5–10 nm on the surface of few-layer Ti3C2 to develop a sandwich-like hierarchical structure of Ti3C2/In4SnS8 nanohybrid via in situ hydrothermal strategy. The enlarged interfacial area and close contact between Ti3C2 and In4SnS8 benefit for carrier transportation among nanohybrids. Characterization through X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) corroborates the successful construction of Ti3C2/In4SnS8 nanostructures. Band structures investigation including valence band maximum and Mott-Schottky plots reveals the formation of Schottky junction in this 2D/2D heterostructure, that favors for ultrafast charge carrier separation and transportation from In4SnS8 to Ti3C2 and preventing the electrons backflow from Ti3C2 to In4SnS8. Photoluminescene analysis and photo/electrochemical measurements prove that the combination of Ti3C2 and In4SnS8 accelerates the transportation of photoexcited electron-hole pairs and efficiently suppresses charge carrier recombination. Unsurprisingly, 7 wt% Ti3C2/In4SnS8 catalysts exhibit the highest visible-light-driven photoreactivity with H2O2 production rates of 1.998 µmol∙L−1∙min‒1 that is 2.2 times larger than that of single In4SnS8. Additionally, Ti3C2/In4SnS8 demonstrates a multifunctional capability in Cr(Ⅵ) reduction with the greatest reaction rates of 19.8 × 10−3 min‒1 that is almost 4-fold larger than that of individual semiconductor. Moreover, the nanohybrids exhibit excellent photostability after 5 cycles testing in both reaction systems. The morphology, crystal structure and composition for Ti3C2/In4SnS8 remain unaltered after photoreaction. A comprehensive analysis including trapping agents and atmosphere experiments as well as electron paramagnetic resonance demonstrates that the H2O2 evolution pathway consists of two channels: a two-step successive 1e‒ oxygen reduction reaction and a one-step 2e‒ water oxidation reaction. This work may provide a viable protocol for designing efficient and multifunctional photocatalytic systems for solar-to-chemical energy conversion.

Key words: Ti3C2, In4SnS8, Photocatalysis, H2O2 production, Cr(Ⅵ) reduction