物理化学学报 >> 2021, Vol. 37 >> Issue (6): 2009097.doi: 10.3866/PKU.WHXB202009097

所属专题: 先进光催化剂设计与制备

论文 上一篇    下一篇

微波辅助快速制备2D/1D ZnIn2S4/TiO2 S型异质结及其光催化制氢性能

梅子慧, 王国宏(), 严素定, 王娟   

  • 收稿日期:2020-09-29 录用日期:2020-10-31 发布日期:2020-11-10
  • 通讯作者: 王国宏 E-mail:wanggh2003@163.com
  • 基金资助:
    国家自然科学基金(22075072);国家自然科学基金(52003079);湖北省自然科学基金(2019CFB568)

Rapid Microwave-Assisted Synthesis of 2D/1D ZnIn2S4/TiO2 S-Scheme Heterojunction for Catalyzing Photocatalytic Hydrogen Evolution

Zihui Mei, Guohong Wang(), Suding Yan, Juan Wang   

  • Received:2020-09-29 Accepted:2020-10-31 Published:2020-11-10
  • Contact: Guohong Wang E-mail:wanggh2003@163.com
  • About author:Guohong Wang, E-mail: wanggh2003@163.com
  • Supported by:
    the National Natural Science Foundation of China(22075072);the National Natural Science Foundation of China(52003079);Hubei Provincial Natural Science Foundation of China(2019CFB568)

摘要:

能源危机的威胁在过去二十年里引起了全球性广泛关注。由于地球上具有丰富的太阳能和水资源,光催化分解水制氢被认为是获取绿色能源的一种有效途径。迄今为止,许多光催化剂已经得到了深入研究。其中,TiO2以其无毒、化学稳定性高、形态可控、光催化活性强等优点得到了广泛的关注。特别是1D结构的TiO2纳米纤维具有独特的一维电子转移轨迹,较大的吸附能力和较高的光生电子-空穴对(e--h+)传输速率等优点在光催化领域更是受到研究人员的青睐。尽管如此,TiO2仍存在带隙大、光生电子-空穴对复合速率快等缺点,使其在制氢反应(HER)中效率不高。因此,构建高性能、经济、环保的光催化剂是实现太阳能高效转化的一大挑战。最近,各种提高TiO2光催化活性的策略得到了广泛研究,包括与窄带隙半导体(如ZnIn2S4)的耦合等。另外,微波辅助合成技术以其成本低、设备简单、环境无污染、反应速度快等优点,已成为制备光催化半导体材料的一种重要手段。在本工作中,为解决TiO2带隙宽(约3.2 eV)和电子-空穴对复合速率快等缺点,通过微波辅助合成技术快速地将2D结构的ZnIn2S4纳米片原位组装在TiO2纳米纤维上,构筑2D/1D ZnIn2S4/TiO2 S型异质结。通过调节ZnIn2S4前驱体与TiO2 NFs的摩尔比,可以很容易地控制TiO2纳米纤维上ZnIn2S4负载量。实验结果表明:相对于纯ZnIn2S4和TiO2而言,ZnIn2S4/TiO2异质结光催化剂在太阳光照射下的光吸收和制氢性能得到明显提高。在优化条件下,样品ZT-0.5 (ZnIn2S4与TiO2的摩尔比为0.5)具有最佳制氢性能,达到8774 μmol·g-1·h-1,分别是纯TiO2纳米纤维(3312 μmol·g-1·h-1)和ZnIn2S4 (3114 μmol·g-1·h-1)纳米片的2.7倍和2.8倍。基于实验结果,我们提出来一种在ZnIn2S4和TiO2间形成的S型异质结机理,并很好地阐释了ZnIn2S4/TiO2复合材料光催化制氢活性增强的原因。

关键词: 微波辅助法, 2D/1D, ZnIn2S4/TiO2, S型异质结, 光催化制氢

Abstract:

The threat and global concern of energy crises have significantly increased over the last two decades. Because solar light and water are abundant on earth, photocatalytic hydrogen evolution through water splitting has been considered as a promising route to produce green energy. Therefore, semiconductor photocatalysts play a key role in transforming sunlight and water to hydrogen energy. To date, various photocatalysts have been studied. Among them, TiO2 has been extensively investigated because of its non-toxicity, high chemical stability, controllable morphology, and high photocatalytic activity. In particular, 1D TiO2 nanofibers (NFs) have attracted increasing attention as effective photocatalysts because of their unique 1D electron transfer pathway, high adsorption capacity, and high photoinduced electron–hole pair transfer capability. However, TiO2 NFs are considered as an inefficient photocatalyst for the hydrogen evolution reaction (HER) because of their disadvantages such as a large band gap (~3.2 eV) and fast recombination of photoinduced electron–hole pairs. Therefore, the development of a high-performance TiO2 NF photocatalyst is required for efficient solar light conversion. In recent years, several strategies have been explored to improve the photocatalytic activity of TiO2 NFs, including coupling with narrow-bandgap semiconductors (such as ZnIn2S4). Recently, microwave (MW)-assisted synthesis has been considered as an important strategy for the preparation of photocatalyst semiconductors because of its low cost, environment-friendliness, simplicity, and high reaction rate. Herein, to overcome the above-mentioned limiting properties of TiO2 NFs, we report a 2D/1D ZnIn2S4/TiO2 S-scheme heterojunction synthesized through a microwave (MW)-assisted process. Herein, the 2D/1D ZnIn2S4/TiO2 S-scheme heterojunction was constructed rapidly by using in situ 2D ZnIn2S4nanosheets decorated on 1D TiO2 NFs. The loading of ZnIn2S4 nanoplates on the TiO2 NFs could be easily controlled by adjusting the molar ratios of ZnIn2S4 precursors to TiO2 NFs. The photocatalytic activity of the as-prepared samples for water splitting under simulated solar light irradiation was assessed. The experimental results showed that the photocatalytic performance of the ZnIn2S4/TiO2 composites was significantly improved, and the obtained ZnIn2S4/TiO2 composites showed increased optical absorption. Under optimal conditions, the highest HER rate of the ZT-0.5 (molar ratio of ZnIn2S4/TiO2= 0.5) sample was 8774 μmol·g-1·h-1, which is considerably higher than those of pure TiO2 NFs (3312 μmol·g-1·h-1) and ZnIn2S4nanoplates (3114 μmol·g-1·h-1) by factors of 2.7 and 2.8, respectively. Based on the experimental data and Mott-Schottky analysis, a possible mechanism for the formation of the S-scheme heterojunction between ZnIn2S4 and TiO2 was proposed to interpret the enhanced HER activity of the ZnIn2S4/TiO2heterojunctionphotocatalysts.

Key words: Microwave-assisted, 2D/1D, ZnIn2S4/TiO2, S-scheme heterojunction, Photocatalytic hydrogen evolution

MSC2000: 

  • O649