物理化学学报 >> 2025, Vol. 41 >> Issue (11): 100148.doi: 10.1016/j.actphy.2025.100148

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TiO2/CdS S型异质结促进光催化CO2甲烷化及其飞秒瞬态吸收光谱机理研究

霍怡廷1,2,3, 周欣2, 赵非凡3, 艾陈斌3, 吴珍2, 常志东1,*(), 朱必成3,*()   

  1. 1 北京科技大学化学与生物工程学院, 北京 100083
    2 鄂尔多斯应用技术学院化学工程学院, 内蒙古 鄂尔多斯 017000
    3 中国地质大学材料与化学学院太阳燃料实验室, 湖北 武汉 430078
  • 收稿日期:2025-07-16 修回日期:2025-07-30 录用日期:2025-08-03 发布日期:2025-09-29
  • 通讯作者: Email: zdchang@ustb.edu.cn (常志东)zhubicheng@cug.edu.cn (朱必成)
  • 基金资助:
    国家自然科学基金(52173065); 国家自然科学基金(22469001); 内蒙古自然科学基金(2025QN05107); 内蒙古自然科学基金(2025ZDLH002)

Boosting photocatalytic CO2 methanation through TiO2/CdS S-scheme heterojunction and fs-TAS mechanism study

Yiting Huo1,2,3, Xin Zhou2, Feifan Zhao3, Chenbin Ai3, Zhen Wu2, Zhidong Chang1,*(), Bicheng Zhu3,*()   

  1. 1 School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China
    2 School of Chemical Engineering, Ordos Institute of Technology, Ordos, 017000, Inner Mongolia, China
    3 Laboratory of Solar Fuel, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430078, Hubei Province, China
  • Received:2025-07-16 Revised:2025-07-30 Accepted:2025-08-03 Published:2025-09-29
  • Contact: Email: zdchang@ustb.edu.cn (Zhidong Chang)zhubicheng@cug.edu.cn (Bicheng Zhu)
  • Supported by:
    the National Natural Science Foundation of China(52173065); the National Natural Science Foundation of China(22469001); Natural Science Foundation of Inner Mongolia Autonomous Region of China(2025QN05107); Natural Science Foundation of Inner Mongolia Autonomous Region of China(2025ZDLH002)

摘要:

通过光催化将CO2转化为高附加值碳氢化合物在可持续能源领域具有巨大潜力,但实现高活性和选择性仍然具有挑战性。本文中,一种新型的TiO2/CdS异质结光催化剂在光催化CO2还原中表现出优异的性能。优化后的催化剂的CH4产率比纯TiO2提高了4.2倍,且对CH4的选择性高达65.4% (CO为34.6%)。其增强的活性源于独特的形貌,促进了CO2的吸附和传质,以及CdS与TiO2之间形成紧密的S型异质结,这提高了电荷分离效率,同时保持了强氧化还原电位。并且,飞秒瞬态吸收光谱(fs-TAS)与原位漫反射红外傅里叶变换光谱(DRIFTS)相结合,为光催化二氧化碳还原路径提供了直接证据,并确定了CdS上的硫位点是稳定*CH3O、*CHO和*CO中间体的关键,从而促进选择性生成CH4。此外,基于密度泛函理论(DFT)的理论计算进一步补充了实验结果。计算证实了S型异质结的电子结构特征,揭示了原子尺度上的能级和电荷转移机制。这不仅加深了我们对光催化过程的理解,还为进一步优化光催化剂设计提供了理论基础。总体而言,我们的工作展示了TiO2/CdS异质结光催化剂在光催化CO2还原中的优异性能。

关键词: 光催化CO2还原, 甲烷选择性, fs-TAS, S型异质结

Abstract:

The conversion of CO2 into value-added hydrocarbons via photocatalysis holds great promise for sustainable energy, yet achieving high activity and selectivity remains challenging. Herein, a novel TiO2/CdS heterostructured photocatalyst exhibits exceptional performance in CO2 photoreduction. The optimized catalyst delivers a 4.2-fold increase in CH4 production rate compared to pristine TiO2, with a remarkable 65.4% selectivity toward CH4 (34.6% CO). The enhanced activity arises from the unique morphology, facilitating CO2 adsorption and mass transfer, and the intimate S-scheme heterojunction between CdS and TiO2, which boosts charge separation while preserving strong redox potentials. Critically, femtosecond transient absorption spectroscopy (fs-TAS) combined with in situ DRIFTS provides direct evidence for the S-scheme pathway and identifies sulfur sites on CdS as key for stabilizing *CH3O, *CHO and *CO intermediates, steering selectivity toward CH4. In addition, theoretical calculations based on density functional theory (DFT) further complement the experimental findings. The calculations confirm the electronic structure characteristics of the S-scheme heterojunction, revealing the energy levels and charge transfer mechanisms at the atomic scale. This not only deepens our understanding of the photocatalytic process but also provides a theoretical basis for further optimizing the photocatalyst design. Overall, our work demonstrates the outstanding performance of the TiO2/CdS heterostructured photocatalyst in CO2 photoreduction.

Key words: CO2 photoreduction, Methane selectivity, fs-TAS, S-scheme heterojunction