物理化学学报 >> 2023, Vol. 39 >> Issue (6): 2208030.doi: 10.3866/PKU.WHXB202208030

所属专题： S型光催化剂

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将In2O3/CdSe-DETA纳米复合材料中的电荷转移从Type-I转变为S-Scheme以提高光催化制氢的活性和稳定性

李真1, 刘雯2, 陈春旭1, 马婷婷2, 张金锋3,*(), 王正华2,*()   

  1. 1 安徽科技学院食品工程学院, 安徽 凤阳 233100
    2 安徽师范大学化学与材料科学学院, 安徽 芜湖 241000
    3 淮北师范大学物理与电子信息学院, 安徽 淮北 235000
  • 收稿日期:2022-08-22 录用日期:2022-09-20 发布日期:2022-09-29
  • 通讯作者: 张金锋,王正华 E-mail:zhwang@ahnu.edu.cn;jfzhang@chnu.edu.cn

Transforming the Charge Transfer Mechanism in the In2O3/CdSe-DETA Nanocomposite from Type-I to S-Scheme to Improve Photocatalytic Activity and Stability During Hydrogen Production

Zhen Li1, Wen Liu2, Chunxu Chen1, Tingting Ma2, Jinfeng Zhang3,*(), Zhenghua Wang2,*()   

  1. 1 School of Food Engineering, Anhui Science and Technology University, Fengyang 233100, Anhui Province, China
    2 College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, Anhui Province, China
    3 School of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000, Anhui Province, China
  • Received:2022-08-22 Accepted:2022-09-20 Published:2022-09-29
  • Contact: Jinfeng Zhang, Zhenghua Wang E-mail:zhwang@ahnu.edu.cn;jfzhang@chnu.edu.cn

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摘要：

化石能源的问题限制了人类的发展。解决这个问题的有效方法是发展可持续性的清洁能源。近年来，氢气作为一种新型的清洁能源被争相报道。氢气燃烧热很大，且产物只有水，完全符合绿色环保可持续性能源的特点。因此，解决氢能源的生产方法就可以有效地解决能源危机问题。自TiO2在1972年作为光催化剂分解水产生氢气开始，半导体光催化剂分解水产生氢气登上了历史的舞台。然而，单一组分光催化剂的固有缺点限制了它的实际应用，寻找克服单一组分光催化剂缺点的解决方案仍然具有挑战性。相对于单一的光催化剂，复合材料光催化剂可以更有效地分离光生电子和空穴，增加光催化析氢反应的速率。因此，通过选择复合材料异质结处合适的光催化机制(如：S-scheme)，可以进一步提升催化剂的光催化析氢活性和稳定性。本文通过改变合成条件获得了一系列具有不同带隙宽度的单一CdSe-DETA光催化剂。光催化实验显示调节CdSe-DETA的带隙(2.31 eV)可以获得最佳的光催化产氢活性，但是其稳定性很差。因此，我们将CdSe-DETA纳米花附着在In2O3多孔纳米片表面，构建了In2O3/CdSe-DETA纳米复合材料，以提升光催化析氢活性，稳定性和光电流响应。In2O3/CdSe-DETA纳米复合材料中异质结的类型可随着CdSe-DETA带隙宽度的改变而变化。随着CdSe-DETA带隙宽度的增加，异质结的类型可从Type-I型转变到S-scheme型。相对于单一光催化剂和Type-I型光催化剂，S-scheme型In2O3/CdSe-DETA纳米复合材料具有更高的光催化活性以及良好的稳定性。因此，我们选择S-scheme异质结的In2O3/CdSe-DETA纳米复合材料来获得光催化活性和稳定性的最大收益。此外，我们通过差分电荷密度计算结合实验结果证实了S-scheme异质结的存在。S-scheme异质结In2O3/CdSe-DETA纳米复合材料有效分离了光生电子和空穴，最大程度地利用复合材料的导带和价带，高效且稳定的光催化析氢。本研究展示了一种调制载流子转移机制的策略，可为开发高效的析氢光催化剂提供借鉴。

关键词: 带隙, S-scheme, 理论计算, 析氢, 光腐蚀

Abstract:

The problems associated with fossil fuel consumption are restricting human development and harming the environment. An effective way for solving the alluded problems is to develop technology for harnessing renewable clean energy. In recent years, hydrogen has been reported as a new source of clean energy. The combustion heat of hydrogen is very high and the product formed is only water, which fully conforms to the characteristics of green and sustainable energy. Therefore, finding a suitable method for producing hydrogen can effectively solve the current global energy crisis. Since titanium(IV) oxide was used as a photocatalyst to split water into hydrogen and oxygen in 1972, water splitting over semiconductor photocatalysts has been an interesting research topic in the past decades. Nevertheless, the inherent disadvantages of single-component photocatalysts limit their practical application and it is still challenging to circumvent those disadvantages. When compared with single-component photocatalysts, composite photocatalysts can more effectively separate photogenerated electrons and holes, thereby increasing the photocatalytic hydrogen evolution rate. Therefore, photocatalytic hydrogen evolution activity and stability can be optimized by selecting the appropriate photocatalytic mechanism (e.g., S-scheme) at the heterojunction of composites. In this study, many single-component CdSe-DETA photocatalysts with different band gaps were synthesized by varying certain synthesis conditions. The results obtained showed that adjusting the band gap (2.31 eV) of CdSe-DETA led to superior photocatalytic hydrogen production activity but the stability of the photocatalyst was poor. Thereafter, we constructed an In2O3/CdSe-DETA nanocomposite by attaching CdSe-DETA nanoflowers to the surface of porous In2O3 nanosheets to improve the photocatalytic hydrogen evolution activity, stability, and photocurrent response. The type of heterojunction in the In2O3/CdSe-DETA nanocomposite can be varied through the band energy gap of CdSe-DETA. More specifically, the type of heterojunction can be switched from Type-I to S-scheme in the case of swelling of the band energy gap of CdSe-DETA. When compared with single-component photocatalysts and Type-I photocatalysts, the S-scheme In2O3/CdSe-DETA nanocomposite exhibited higher photocatalytic activity and stability. Therefore, we chose the In2O3/CdSe-DETA nanocomposite with an S-scheme heterojunction to obtain optimal photocatalytic activity and stability. Additionally, we confirmed the existence of an S-scheme heterojunction via differential charge density calculations combined with experimental results. The S-scheme heterojunction In2O3/CdSe-DETA nanocomposite effectively separated photogenerated electrons and holes as well as maximized the use of the conduction and valence bands of the composite for efficient and stable photocatalytic hydrogen evolution. Therefore, this study demonstrates a novel strategy for modulating the carrier transfer mechanism, which provides a reference for the development of efficient hydrogen evolution photocatalysts.

Key words: Band gap, S-scheme, Theoretical calculation, Hydrogen evolution, Photocorrosion