催化学报 ›› 2023, Vol. 44: 146-159.DOI: 10.1016/S1872-2067(22)64155-X

• 论文 • 上一篇    下一篇

2D/2D超薄La2Ti2O7/Ti3C2 Mxene肖特基异质结用于高效光催化CO2还原

王可a,1, 程淼a,1, 王楠a, 张千一a, 刘懿a, 梁俊威a, 管杰b,*(), 刘茂昌c,*(), 周建成a,d, 李乃旭a,d,*()   

  1. a东南大学化学化工学院, 江苏南京 211189
    b东南大学物理学院, 江苏南京 211189
    c西安交通大学动力工程多相流国家重点实验室, 国际可再生能源研究中心, 陕西西安 710049
    d中国林业科学研究院林产化学工业研究所, 江苏省生物质能源与材料重点实验室, 江苏南京 210042
  • 收稿日期:2022-06-14 接受日期:2022-07-18 出版日期:2023-01-18 发布日期:2022-12-08
  • 通讯作者: 管杰,刘茂昌,李乃旭
  • 作者简介:1共同第一作者.
  • 基金资助:
    国家自然科学基金(21576050);国家自然科学基金(21227801);中央高校基本科研业务费项目(3207045403);中央高校基本科研业务费项目(3207042107D);中央高校基本科研业务费项目(3207042108D);江苏省生物质能源与材料重点实验室开放基金资助项目(JSBEM202001);江苏高校优势学科建设工程资助项目(PAPD);东南大学“仲英青年学者”;江苏省研究生科研实践创新计划(SJCX20_0014);江苏省研究生科研实践创新计划(SJCX20_0015)

Inter-plane 2D/2D ultrathin La2Ti2O7/Ti3C2 MXene Schottky heterojunctions toward high-efficiency photocatalytic CO2 reduction

Ke Wanga,1, Miao Chenga,1, Nan Wanga, Qianyi Zhanga, Yi Liua, Junwei Lianga, Jie Guanb,*(), Maochang Liuc,*(), Jiancheng Zhoua,d, Naixu Lia,d,*()   

  1. aSchool of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, Jiangsu, China
    bSchool of Physics, Southeast University, Nanjing 211189, Jiangsu, China
    cInternational Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, China
    dInstitute of Chemical Industry of Forest Products of the Chinese Academy of Forestry Sciences, Jiangsu Key Laboratory for Biomass Energy and Material, Nanjing 210042, Jiangsu, China
  • Received:2022-06-14 Accepted:2022-07-18 Online:2023-01-18 Published:2022-12-08
  • Contact: Jie Guan, Maochang Liu, Naixu Li
  • About author:1 Contributed equally to this work.
  • Supported by:
    National Natural Science Foundation of China(21576050);National Natural Science Foundation of China(21227801);Fundamental Research Funds for the Central Universities of China(3207045403);Fundamental Research Funds for the Central Universities of China(3207042107D);Fundamental Research Funds for the Central Universities of China(3207042108D);Foundation of Jiangsu Key Laboratory for Biomass Energy and Material(JSBEM202001);Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD);Zhongying Young Scholars of Southeast University;Postgraduate Research & Practice Innovation Program of Jiangsu Province(SJCX20_0014);Postgraduate Research & Practice Innovation Program of Jiangsu Province(SJCX20_0015)

摘要:

CO2的过量排放造成了全球生态系统的失衡, 如温室效应、海洋酸化和极端天气频发等. CO2作为一种储量丰富且可循环利用的碳一资源, 利用光催化技术将其催化转化为包括一氧化碳和甲烷在内的碳氢燃料, 为上述问题提供了一个很有前景的解决方案. 纳米片作为典型的二维材料, 其厚度一般低至100 nm. 此外, 二维材料具有较大的比表面积、可调谐的端基官能团、出色的光学性能以及较好的导电性和柔韧性, 在光催化领域受到了广泛关注. 在半导体材料中, 钛酸镧(La2Ti2O7)具有优良的氧化还原能力和良好的稳定性和耐久性, 但与其他半导体类似, La2Ti2O7的宽带隙性质决定了其只能利用波长较短的光, 这极大地限制了其对太阳光的利用.

为了增强光吸收能力, 降低光生载流子的复合, 本文通过溶剂热法在La2Ti2O7纳米片上负载薄层Ti3C2 MXene纳米片, 设计制备了二维/二维(2D/2D) La2Ti2O7/Ti3C2 Mxene肖特基异质结复合材料, 并用于增强光催化CO2还原性能. 研究发现, 当Ti3C2 MXene的负载量为3 wt%时, CO和CH4的产率是物理混合的La2Ti2O7和Ti3C2 MXene的4.6倍和11.4倍. 飞秒瞬态吸收光谱和X射线光电子能谱结果表明, La2Ti2O7/Ti3C2 Mxene较好的光催化CO2还原反应性能归因于高效电荷载流子迁移率和两组分接触界面之间形成了肖特基异质结的协同作用. 原位红外漫反射光谱观察到的反应中间产物、紫外光电子能谱计算得到的功函数和原子层级的密度泛函理论计算得到的吉布斯自由能和差分电荷密度揭示了该体系光催化CO2还原的机理、光催化反应的路径和产物选择性的由来.

相比于单独的La2Ti2O7和物理混合的La2Ti2O7和Ti3C2 MXene, 2D/2D La2Ti2O7/Ti3C2 Mxene肖特基异质结复合材料表现出增强的光催化CO2还原性能. 引入Ti3C2 MXene形成平面间2D/2D的异质结结构可作为电荷转移通道并促进电荷的快速分离, 形成的肖特基结能够有效地抑制光生电子的回流, 同时降低了光催化CO2还原的反应势垒, 最终促进了光催化CO2还原过程. 综上, 本文详细阐述了肖特基异质结构中光催化性能增强的机理机制, 并为设计和制造用于转化和利用二氧化碳的光催化剂及其探究光催化转化机理提供借鉴.

关键词: 钛酸镧, Ti3C2 MXene, 光催化CO2还原, 二维/二维, 肖特基异质结

Abstract:

Ascribing to incremental fossil fuels emissions, the utilization and conversion of CO2 and development of renewable energy is globally essential and significative. Ultrathin 2D/2D heterojunctions with fast photo-generated electrons transmission channels illustrate a better strategy to improve photocatalytic activity. Herein, combing La2Ti2O7 with metallic few-layered Ti3C2 MXene to construct inter-plane 2D/2D heterojunction was in situ self-assembled through solvothermal method. Benefiting from the advantages including stability, conductivity, abundant active sites and formation of Schottky junctions, as expected, the ultrathin 2D/2D La2Ti2O7/Ti3C2 MXene nanosheets presented much improved photocatalytic ability for CO2 reduction to CO and CH4, which is about 4.6 and 11.4 times higher than that of mechanical mixed La2Ti2O7 and Ti3C2 MXene. fs-TAS and XPS provided direct evidence that the prominence of La2Ti2O7/Ti3C2 MXene in photocatalytic CO2 reduction reaction over other opponents should be attributed to the synergetic effect of efficient charge carrier mobility and formed 2D/2D Schottky heterojunction interfacial contact between La2Ti2O7 and Ti3C2 MXene. Intermediates revealed by in-situ DRIFTS and corresponding atomic-level DFT calculations confirmed the mechanism, pathways and selectivity for photocatalytic CO2 conversion. This work expanded promising prospects arouses new impetus for deepening the prehension of the mechanism of photocatalytic CO2 reduction, designing and fabrication of Schottky heterojunctions for application in conversion and utilization of CO2.

Key words: La2Ti2O7, Ti3C2 MXene, Photocatalytic CO2 reduction, 2D/2D, Schottky heterojunction