物理化学学报 >> 2024, Vol. 40 >> Issue (12): 2408002.doi: 10.3866/PKU.WHXB202408002

所属专题: 太阳燃料制备

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原位合成S型氮缺陷ZnWO4/g-C3N4异质结及CO2光还原性能

秦建宇, 安月皎, 张艳峰*()   

  1. 河北师范大学化学与材料科学学院, 河北省无机纳米材料重点实验室, 国家实验化学教学示范中心, 石家庄 050024
  • 收稿日期:2024-08-01 修回日期:2024-09-02 录用日期:2024-09-02 发布日期:2024-11-09
  • 通讯作者: Email: zhangyanfeng@hebtu.edu.cn (张艳峰)
  • 基金资助:
    河北省自然科学基金(B2020205013); 河北省自然科学基金(B2022205008); 河北师范大学科技项目(L2021K01); 河北省创新能力提升计划项目(22567604H)

In Situ Assembled ZnWO4/g-C3N4 S-Scheme Heterojunction with Nitrogen Defect for CO2 Photoreduction

Jianyu Qin, Yuejiao An, Yanfeng Zhang*()   

  1. National Demonstration Center for Experimental Chemistry Education, Hebei Key Laboratory of Inorganic Nano-materials, College of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang 050024, China
  • Received:2024-08-01 Revised:2024-09-02 Accepted:2024-09-02 Published:2024-11-09
  • Contact: Email: zhangyanfeng@hebtu.edu.cn (Yanfeng Zhang)
  • Supported by:
    ebei Provincial Natural Science Foundation(B2020205013); ebei Provincial Natural Science Foundation(B2022205008); Science and Technology Project of Hebei Normal University of China(L2021K01); Innovation Capability Improvement Plan Project of Hebei Province(22567604H)

摘要:

通过半导体光催化将CO2转化为可储存的太阳能燃料是解决温室效应和资源短缺问题的有效策略。然而,光生载流子的快速复合严重限制了单组分催化剂的CO2还原能力。合成具有缺陷的S型异质结可以有效地分离光生电子和空穴,增强对非极性分子的吸附和活化。本文采用原位合成的方法构建了具有缺陷的S型ZnWO4/g-C3N4异质结。结果表明,CO2还原产生CO的速率高达232.4 μmol∙g−1∙h−1,选择性接近100%,分别是原始ZnWO4和g-C3N4的11.6倍和8.5倍。原位XPS和功函数分析证明了S型电荷转移路径。S型异质结实现了电子-空穴的有效空间分离,促进了CO2的还原。原位ESR表明CO2分子被氮空位吸附,氮空位是光催化反应中的电子受体,有利于电子捕获和分离。S型电荷转移模式和氮空位共同促进了CO2高效还原。这项工作为了解S型电荷转移机理和缺陷在调节CO2还原活性方面的协同作用提供了重要见解。

关键词: S型异质结, ZnWO4, g-C3N4, 氮空位, CO2光还原

Abstract:

Reforming CO2 into storable solar fuels via semiconductor photocatalysis is considered an effective strategy to solve the greenhouse effect and resource shortage. Unfortunately, the problem of rapid photogenerated carriers severely limits the CO2 reduction capability of one-component catalysts. The fabrication of S-scheme heterojunctions with defects can result in efficient spatial separation of photo-generated charge carriers and increase adsorption and activation of nonpolar molecules. Herein, ZnWO4/g-C3N4 S-scheme heterojunctions with defects are constructed through in situ growth method. The experiments show that the generation rate of CO from CO2 reduction is up to 232.4 μmol∙g−1∙h−1 with a selectivity close to 100%, which is 11.6 and 8.5 times higher than those of pristine ZnWO4 and g-C3N4, respectively. In situ XPS and work function analyses demonstrate the S-scheme charge transport pathway, which facilitates the spatial segregation of photogenerated carriers and promotes CO2 reduction. In situ ESR illustrates that CO₂ molecules are adsorbed by nitrogen vacancies, which act as photoelectron acceptors during the photocatalytic reaction and are favorable for charge trapping and separation. The S-scheme charge transport mode and nitrogen vacancy work together to stimulate the efficient conversion of CO2 to CO. This work presents significant insights to the cooperative influence of the S-scheme charge transport mode and defects in regulating CO2 reduction activity.

Key words: S-scheme heterojunction, ZnWO4, g-C3N4, Nitrogen vacancy, CO2 photoreduction