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电化学(中英文) ›› 2021, Vol. 27 ›› Issue (5): 570-578.  doi: 10.13208/j.electrochem.201109

• 论文 • 上一篇    下一篇

高导电性和催化活性的Janus-TiNbCO2析氢反应催化材料

徐黎黎1,*(), 任冬燕1, 赵骁锋2,3,*(), 易勇2   

  1. 1.绵阳职业技术学院,材料工程系,四川 绵阳 621000
    2.西南科技大学,材料科学与工程学院,四川 绵阳 621010
    3.乌普萨拉大学,物理与天文学系,瑞典 乌普萨拉SE-75120
  • 收稿日期:2020-11-09 修回日期:2020-12-22 出版日期:2021-10-28 发布日期:2021-02-09
  • 通讯作者: 徐黎黎,赵骁锋 E-mail:ll-xu2008@163.com;xfz_33@126.com
  • 基金资助:
    国家自然科学基金项目(12105236)

Janus-TiNbCO2 for Hydrogen Evolution Reaction with High Conductivity and Catalytic Activity

Li-Li Xu1,*(), Dong-Yan Ren1, Xiao-Feng Zhao2,3,*(), Yong Yi2   

  1. 1. Mianyang Vocational and Technical College, Department of Materials Enginerring, Mianyang 621000, Sichuan, China
    2. School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan, China
    3. Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden
  • Received:2020-11-09 Revised:2020-12-22 Published:2021-10-28 Online:2021-02-09
  • Contact: Li-Li Xu,Xiao-Feng Zhao E-mail:ll-xu2008@163.com;xfz_33@126.com

摘要:

探寻具有高导电性和高催化活性的析氢反应(HER)催化材料一直是可持续能源发展研究中的热点。Ti2C具有表面活性位点多和优良的力学稳定性、导电性等,已成为潜在的制氢催化剂。然而,终端O修饰Ti2C表面,会降低该材料的导电性,进而限制了电子在价带与导带间的输运。本研究通过Nb掺杂,构建双电层Janus-TiNbCO2,并借助VASP软件研究了Janus-TiNbCO2的能带结构、HER性能和HER反应路径过渡态。结果表明,Janus-TiNb-CO2为导体材料,其在应力、氧空位缺陷和H*覆盖度的影响下,均表现出极优异的催化活性,计算获得的最优ΔGH*值为0.02 eV。H*在Janus-TiNbCO2上可能以Heyrovsky路径进行反应,该路径的迁移能势垒为0.23 eV。Janus-TiNbCO2是一种具有HER应用前景的催化材料。

关键词: MXene, Janus-TiNbCO2, 能带, 析氢反应

Abstract:

Exploring the potential hydrogen evolution reaction (HER) catalysts with the high activity and high conductivity has always been a hot spot in the research of renewable energy development. Ti2C, as one of the 2D-MXene, has excellent properties relating to many active sites, mechanical stability, conductivity, etc., and has become a potential HER catalyst. However, the modification of the surface of Ti2C by terminal O will reduce the conductivity, thereby limiting the transport of electrons between the valence band and the conduction band. In this study, an electric double layer Janus-TiNbCO2 was constructed by Nb doping. The band property, HER activity and HER reaction path of Janus-TiNbCO2 are studied by the first-principles calculations. The results show that Nb doping increases the distance between Ti and O atoms, which increases the lattice parameters of Janus-TiNbCO2 comparing with that of Ti2CO2 structure. The Janus-TiNbCO2 structure is stable by calculating the thermodynamic stability at 500 K using AIMD method. The band gap of Ti2CO2 is approximate 0.9 eV. After Nb doping, the orbital hybridization between Nd-3d and O-2p affects the electronic rearrangement of Ti-3d, leading that Janus-TiNbCO2 has the metal band structure. In Janus-TiNbCO2, both Ti and Nb surfaces adsorb H* by O site, where the ΔGH*(@Ti) = -0.55 eV,ΔGH*(@Nb) = 0.02 eV, showing Ti and Nb surfaces have different catalytic activities. Comparing with graphenes, e.g., h-B2O, Pt, and g-C3N4, Janus-TiNbCO2 has better catalytic activity. The charge distribution of Janus-TiNbCO2 near the Fermi level was analyzed by HSE-06 function. The result reveals that O atoms on the Ti surface exhibit charge unsaturation at the Fermi level, while those on Nb surface strong saturation. Moreover, the effects of H* coverage and strains(+2% ~ +4%) on the catalyst activity of Janus-TiNbCO2 are studied. When the H* coverage is low, the optimal ΔGH* of Nb surface is approximate 0.02 eV, while Ti surface has an excellent catalytic activity at high H* coverages (θ = 7/9, ΔGH* = -0.06 eV). Under the strain action, the H* coverage on surface is not affected. However, strains will reduce the HER activity of Nb surface, and increase the HER activity of Ti surface. Furthermore, oxygen defect is a stable point defect in Janus-TiNbCO2 . Oxygen defect will increase the HER activity of Ti surface and decrease the HER activity of Nb surface. Comparing to the Tafel pathway, the Heyrovsky is a more suitable pathway for the HER, in which the migration barrier of Heyrovsky is 0.23 eV for H* on Nb surface. Janus-TiNbCO2 can be used as a potential HER catalyst.

Key words: MXene, Janus-TiNbCO2, band, hydrogen evolution reaction